Well it's mostly because I used to watch Teen Wolf and THREE actors from that show are voicing characters so XD

Gideon Emery (previously in Final Fantasy XII as Balthier, and Deucalion on Teen Wolf) is voicing Biggs
Tyler Hoechlin (Derek Hale in Teen Wolf, also know for being Clark Kent/Superman on Supergirl) is voicing Sephiroth
and, in his first ever voice acting role, Cody Christian (Theo Raeken on Teen Wolf, and Asher Adams on All American) is voicing our boy Cloud Strife

I don't know any of the other released cast although seem to be predominantly people who work in television. Here's a list of who we know so far - https://ariaalways.tumblr.com/post/185529767791/demifiendrsa-final-fantasy-vii-remake-trailer

Also Steve Burton posted a video on twitter about how happy he is to have been Cloud the last 17 years and that he's looking forward to the new cast and Cody Christian replied to say thank you and how honoured he is and I just have all the feels right now