You mean in the shop!
Please, do read www.cregox.com/your-home as I just updated it.
The easiest way to do this is to simply use blog posts instead of galleries or commerce. You can still use summary block there. I'm not sure there's any template that do use squarespace's commerce ability to have comments (with like and share buttons). I know some will support it on galleries too, but often not as fully as blog.
Anyway, it will be U$321 upfront to get me started. I'll look deeper into this and see what I can do for that price then, if you agree, I'll do it within 1 week from payment (again, pleae do read the site).
As for your concerns: