Ah, the website has changed slightly since my post. I would ideally want the phone icon to look the same as the email icon.
The issue I am having with both versions is that one of them is a social link (the email) and one is a button (the phone) and I can't seem to get them to look and act the same. I also would like to keep the hamburger menu button on the mobile version, but I understand if that is a bit of a squeeze on the mobile header.