Is it possible and if so how hard it is to change the word "Spaces" for the groups?
Also, I had some difficulty trying to migrate my users from buddypress and I think it is because I was on BuddyBoss before which changed some tables or file structure. Is there a way to overcome this issue. It would not bring over all the users.
if you want to change the phrases, you can use a plugin like Loco Translate to change the language.