SnazzyView

Yes, I wrote a blog post about how to make a pop-up appear when a user adds an item to their cart which gives them the option to continue shopping or proceed to their cart. 
https://thompsonweb.design/squarespace-website-tips/added-to-cart-pop-up

I’m assuming that you are referring to the plugins that display a little pop-up when you hover over a specific word. If so I have linked to a plugin for Squarespace below, its not automatic like the Wordpress ones so there will be a bit of manual work. 
https://noughtsandones.com/plugins/text-tool-tip

I'm assuming that you're not actually offering the properties for purchase directly off your website. If that is the case I would simply set the price to 0, then depending on which template you are using you can hide the price in the style editor. 
From there I would manually enter the price into the product overview text.
The only real downside I can see is that you won't be able to display the price of the main product overview page, product blocks...

Try putting the below in the order confirmation code injector instead.
<div class="redirect-text"> <h2>Thank You for your Order.... onward to the the General Info Page!</h2> </div> <script> $('.redirect-text').insertAfter('#confirmed-page'); </script>  

Sorry, I forgot that you will also need to load the jQuery library as well for that to work. You will need to add the below to your websites global code injector header.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>  

I think Squarespace is down which is why we're getting the 503 message. 
As for the redirect message I do know how to do this I will just need to wait for Squarespace to backup and running. Did you still want the order confirmation information (order number, total...) to still display or would you prefer for this to stay hidden and just display the message?

I think Squarespace is down which is why we're getting the 503 message. 
As for the redirect message I do know how to do this I will just need to wait for Squarespace to backup and running. Did you still want the order confirmation information (order number, total...) to still display or would you prefer for this to stay hidden and just display the message?

When you add a meta refresh statement to Settings > Advanced > Code Injection > Order Confirmation Page you can choose the delay before the page will redirect. 
For example, the zero in this statement will cause it to redirect to the selected page (www.squarespace.com in this example) immediately. 
<meta http-equiv="refresh" content="0;url=https://www.squarespace.com/" />
Whereas in this statement, the '5' will cause it to redirect after five seconds.
<meta http-equiv="refresh" content="5;url=https://www.squarespace.com/" />
Changing it to 10 would delay the redirect for 10 seconds and so on.
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Hi there,
It can take up to 72 hours for your website to fully switch over. Clearing your cache won’t speed anything up because it’s the cache on servers such  as those of ISPs. Once those caches have been fully updated then people will be redirected to your new website but it will take some time. 
 
https://support.squarespace.com/hc/en-us/articles/206206678-Why-domain-updates-take-up-to-72-hours

Unfortunately Squarespace are rather secretive around  v7.1 just like they are everything else. For me personally v7.1 can't replace v7 without some big improvements to the header, like you mentioned secondary navigation.
It would be nice to get some sort of direction or even stability from Squarespace regarding what they have planned but we probably won't hear anything until their test is over. But I know that they do plan on supporting v7 for some time to come, they just can't guarantee new features will make it to v7.

Unfortunately Squarespace are rather secretive around  v7.1 just like they are everything else. For me personally v7.1 can't replace v7 without some big improvements to the header, like you mentioned secondary navigation.
It would be nice to get some sort of direction or even stability from Squarespace regarding what they have planned but we probably won't hear anything until their test is over. But I know that they do plan on supporting v7 for some time to come, they just can't guarantee new features will make it to v7.

Yes and no, you could achieve it with CSS but you would need to set the name field to make it not mandatory. If you would like to do this just enter the below into your websites global CSS.
.last-name { display:none; } But if you want to just collect somebody's first name then I would just recommend using the text field instead and just calling it first name.
https://support.squarespace.com/hc/en-us/articles/205814018#toc-text

Yes, SQSPThemes / @RasOmari wrote a blog post which I have linked below on how to add a tagline to your mobile header.
https://www.sqspthemes.com/blog/display-tagline-on-mobile-brine-fam

SQSPThemes / @RasOmari sell a plugin that will do exactly what you want (linked below).
https://www.sqspthemes.com/plugins/gallery-random-order

It might be theoretically possible to design and develop your own implementation, though the cost might exceed a couple year's worth of the difference between Squarespace plans. In addition, once you get into sending emails, usually a third-party service of some kind is engaged (and therefore additional ongoing service fees), so the savings might be quite minimal. What plan are you on now? Do you use customer accounts and, if not, how would you go about getting the user's email address? How many emails would you anticipate sending per month?

As @ThompsonWebDesign says, this isn't a feature and cannot be coded around.
You can submit a feature request via Squarespace Customer Care.