It seems to me a fine idea, to see what sort of use classical composers have made of the tradition. As Dick so rightly says, they are no more at variance with that tradition than the sort of arrangements used during the electric folk-rock era. & it's not as if you will be having them every time.

I take it that they will be main guests, climax of an evening of varied folk, and will not be the sole performers that session?; that at least was the norm when I used to attend folk clubs, and ran one near Cambridge, 40+ years ago.

Wish you a successful occasion.

~Michael~