The more I play, the more I think that
1. This first act should just let you have all of the companions with you at all time if you want.
2. But them I'm fine with the the "you have to lock in, for the following acts".
Yes, with #2 you'll miss some of the story options, but that's life -- and replayability.
When there are further companion possibilities added in, maybe some of them will specifically refuse to work together, limiting your party size naturally (so it isn't, like, ten people all traveling around).
