This may sound a bit weird, but a friend who was a singer in a similar kind of group used to talk about her first days with the group, and she once said that she had started off thinking about the instruments around her as a sort of background, like you might sing to a record, or fronting a big band; but very quickly she realized that this was a kind of fear, as if she wasn't a part of the group, and also that there was so much going on that she had to wall everyone off as a single accompanying sound. And then she had got into a kind of slow experimenting, doing things like trying to find the instrument whose timbre was closest to her voice, and working with that for awhile, and then listening to how that instrument worked with others and imitating that, and then shifting to other instruments, timbres, rhythms, etc., and then working back to how the voice had all those potentially and also had its own autonomy as an instrument. Never having been a singer with a group like that, I don't know whether it is any good as advice, but it struck me at the time as a fascinating way of thinking about, and perhaps getting into singing with a group. (It may work better for jazz than folk).

Yours, Peter T.