You can make avatars rectangular by changing the following css in templates/base/css/default.css:
.bx-def-thumbnail {
border-radius: 3px;
-moz-border-radius: 3px;
-webkit-border-radius: 3px;
It will change it almost everywhere.
You can also use another template from the market, when it will be some for 7.2 version.

You can re-arrange block on profile page from admin panel > builders > pages builder. Users can re-arrange own profile's blocks with help of 3rd-party modules - see more

You need to switch to "Embed" option on video upload page and insert youtube link.

Most modules from 7.1 should be compatible with 7.2, I think that developers will update their's mods compatibility when 7.2 release will be available. But it is always better to ask particular author. There is also a community list of compatible modules:
Thanks for your reply, AlexT. I will purchase the new 7.2 version of Dolphin as soon as it is ready.
That list is not very complete.
Below is the legacy version of the Boonex site, maintained for Dolphin.Pro 7.x support.
The new Dolphin solution is powered by UNA Community Management System.