derricksrandomviews

Assign someone editor permissions. They can do anything to a blog post that you can do. 
https://support.squarespace.com/hc/en-us/articles/206537297-Squarespace-permissions-explained

Okay, this is a blog issue, not a page issue. 7.1 blog post pages do not have Fluid Engine so they work a bit like 7.0. I will start from scratch. You edit a post and maybe a section.  To add a  block you hover over a text block (and one may pop up on its own) or any other block until it gets a blue frame and + signs on the top and bottom. You click one of those + depending on where you want the block, in your case a video block. Add your video, like you would any other page on your site. Now comes the fun part. You have to use spacer blocks on each side of the video block to size it. You add them one at a time. You add one then drag it over to one side until a vertical blue line appears but you don't want that line to go up any further than the block or it will shift your whole page to the right if you moved the spacer to the left side of your video block. Once you have one positioned correctly add another one, position it, and then resize the blocks to push the video block to the size you want it to be, it will keep the same aspect ratio. Don't forget to hit done and save (yes I have forgotten).

Thanks so much.

I encountered the same problem, and solved the sizing issue with Derrick's suggestion. Thank you so much for your sharing!

The link is now active: http://www.showoffaustralia.com.au

Okay, this is a blog issue, not a page issue. 7.1 blog post pages do not have Fluid Engine so they work a bit like 7.0. I will start from scratch. You edit a post and maybe a section.  To add a  block you hover over a text block (and one may pop up on its own) or any other block until it gets a blue frame and + signs on the top and bottom. You click one of those + depending on where you want the block, in your case a video block. Add your video, like you would any other page on your site. Now comes the fun part. You have to use spacer blocks on each side of the video block to size it. You add them one at a time. You add one then drag it over to one side until a vertical blue line appears but you don't want that line to go up any further than the block or it will shift your whole page to the right if you moved the spacer to the left side of your video block. Once you have one positioned correctly add another one, position it, and then resize the blocks to push the video block to the size you want it to be, it will keep the same aspect ratio. Don't forget to hit done and save (yes I have forgotten).

Not without password protecting your site. Any method can be worked around including this one: 
https://fingerprint.com/blog/permanently-ban-users/

My site, the landing page first, then the photos page, then all the rest. I guess I am most proud of the images I have on the site.
my random views

There is no official word on when or if this will happen. 

The Wexley Gallery Pages are designed to be dynamic, they move images, resize them, all to keep the look on any sized screen. To fix the number of images per row, use a gallery block as opposed to a gallery page. You can set this up in your unlinked section, create a blank page add a gallery block and in the design you can set the number of images PER ROW to what you want. If you want two images the block will always show two. Once you have built the page or pages, you can move them to the linked section and if you want make one your home page and rename them to take the place of any page you no longer want. If you need any help with this just let me know. 
I have built two sites on Wexley and this does work,  I am using this feature on this Wexley site in some of the gallery/blog posts. A gallery block works the same in a blog or on a page.  
https://christinegregoryphotography.com/

I posted this response to a very recent question about the 20-post limit on a blog page and the 30-post limit using summary blocks and pagination.  In your case, summary blocks will take care of your issue. The rest of my answer is just a bonus. 
Summary blocks go on a page but are not pages themselves so there is no pagination. But there is a work-a-round. Let me address the 30-item limit first. 
You can chain summary blocks together on the same page. You can have as many items as you want by setting the blocks to 30 items and filtering by category or tags. It takes a bit of time to set up and then becomes simple to add a post to. Give your first 30 posts a cat or tag name or number that you can keep up with like"First 30" then give posts 31-60 "Second 30" and so on. Or you can be more specific and group your posts by news subject. The blocks don't have to have 30 entries and still put them on one page.  You can hide the cats if you wish. The actual blog where the posts reside will go into the unlinked section of your site. The summary block page will now act as your front-facing blog page.  You will need to swap the URL slugs.
Pagination:
You can have pagination if you use a second blog full of summary blocks as opposed to a standard page or section.  I have over 80 posts on one long scrolling page on my site. I also have some photography lessons grouped in their own block tied to the Nav bar but they are still part of the main page. Summary blocks are very versatile, and when combined in a second blog can be accessed by a menu.
 You can see my layout here. Click on any group title to see the pagination. Click on an individual item to go to the actual post of course. Check out the pull-down subject menu as well.  This design works for both 7.0 and 7.1.  I used Custom CSS to give the summary blocks a unique look that ties in with my picture galleries and my home page.  
https://myrandomviews.com/blogsummary
my random views Home page. 

There is no built in design path from 7.0 to 7.1. You would basically start a 7.1 site from scratch. You can however use copy and paste for text, which can help "move" blog posts and text blocks. 

You can chain summary blocks together on a page and get over 30 by using filters, for example: give all posts in the first block  category group 1 and the next 30 in their own block category group 2 etc. Using this method I have over 80 posts on one page.

https://www.squarespace.com/templates/wexley-demo just wait a few seconds for your screen to update, and you should be able to click on the black button" start with this design" up in the corner. Worked for me just now.  Wexley is one of my favorite templates, great for photographers like this one that I built:
https://christinegregoryphotography.com/
Christine and I have added some Custom CSS code over time that helps visitors enjoy her site a bit more. I provide that code to anyone who wants it.
If you need any advice using this template, just ask and I will certainly help out. 
 

I don't know if I would call it simple but here is the guide, the guide for both Hubspot and Squarespace so look over the whole guide. It is a couple of years old so hopefully nothing has changed since then. 
https://blog.hubspot.com/marketing/facebook-feed-on-website

The number one reason images fail to upload is while they are going up if you chose  any other  tab, like design it will make the upload quit with an error notice sometimes,  but usually no notice. It just isn't there. So when uploading don't choose any other options. Slow internet speed causes failure to upload. We have a lot of that going on right now. Upload one at a time, don't drag too many into the box, makes things too slow, one may load the others fail. 

Just put the form on a new page in the unlinked section of your site. Assign it a simple url slug and an access password code. It can have only one password to be shared by all visitors however. An account is not necessary. If you really need to assign different passwords then duplicate the page and give each dup it's own passcode.
 

You may need to contact SS technical support.

I accessed your new account and it is now on your new dashboard. 

You don't have to have two accounts to have two sites. You can log on to a dashboard and then choose which site to work on. You can use same log on credentials and payment info or use two payments. Its up to you.  You cannot use two templates for one site.  You can have two sites linked together thru urls, so you would need two domains, one can be internal. What some do in a case like this is build two sites and connect them using a landing page for one site with links to both. . This means one site would need to be 7.0 and one could be 7.0 or 7.1 but I suggest 7.0 for both, just because it gives you more flexibility and the config would be easier to use if they are the same. You can use two templates from the same family one for each site, make them look very different but still find them similiar to set up, for example, Brine and Pacific from 7.0. Same template family but different looks.  

From Google: While Google does not use these reports to take direct action against violations, these reports still play a significant role in helping us understand how to improve our spam detection systems that protect our search results.

Each Archive Block supports one Group By option. To divide content in multiple ways, add multiple Archive Blocks. For example, you can add one Archive Block that lists content by tag and another that lists content by month. Archive Blocks can display up to 50 groups (months, years, authors, categories, or tags) with a maximum of 100 items per group.

Yes, it was the guide to using index pages. 
https://laurentaylar.com/blog/squarespace-index-pages 
It seems to me that what you want to do is easier with image blocks and gallery blocks on a page that is not a gallery section but can be a page in the index. If you can post your website address so we can take a look that might help us to help you easier. 

I think you can adjust the caption fonts in site styles.  Spaces between image blocks and gallery blocks can be adjusted with a combo of padding controls in site styles and using spacers on the page as well. Spacer blocks can be a bit tricky when positioning them, Watch the vertical blue line and make sure it doesn't "grow" up beyond the block you are working with, or your whole page will shift.