Well personally, I would have no problem with you using some of the music in a free game. However when it comes down to the fact that I made this for another team it becomes a bit murkier if you get what I mean.
I personally don't know if they'd be happy with me licensing out music I made for them to somebody else.
If it was a free game on Itch.io I imagine I could work out a way that you could use some/all of it after chatting with the team members. With donations enabled would be fine unless you somehow ended up making a fortune out of the game.
Again I’m not 100% sure if I could negotiate this, but I would do my best to try.
I don't really know if it'd be possible to convince the team to let you use the music for a commercial game, and even if they were, I'd want some kind of financial deal/contract with you.