I know that all the cast will be voiced in english in battle but what about during a cutscene? In the japanese version there were some scenes that were fully voiced, will the english version have it or leave it with just text?
SC is pretty much like FC with the amount of voices, there actually aren't any voiced cutscenes even in Japanese. You're probably thinking of later games like Ao and Zero. I know Ao has voiced cutscenes, not so sure about Zero since I've not played any of that one myself.
Yeah, the first three games have no voiced cutscenes at all. From Zero onwards, they do but it's usually fairly limited even then; the original releases of Zero and Ao only have some lines in some scenes voiced, the rest is still text-only.