bw: in your list of "had Eileen McGann, David Francey. We have 3 more in the works, for Katherine Wheatley, Rick Fines, and Dave Clarke." you have only one trad performer (presuming you mean Eileen)? I beg to differ. Look at where some of those folks are coming from. Rick Fines writes his own songs but has a virtuostic and encyclopaedic understanding of traditional blues guitar. Dave Clarke is really a bluegrass picker par excellence. Francey (my new neighbour whom I haven't yet spoken to) is clearly influenced, lyrically and tunewise, by his Scottish background, and as was mentioned, also sings old songs. (Katherine Wheatley I'll grant you is a contemporary songwriter, but you booked her for the same reason I did--she is very very good.)

Ian Robb, I think, made an interesting observation in his Sing Out! column: a lot of folk performers start out performing trad and when they turn professional switch to doing more and more original material.
Not too many stay in the same idiom throughout their careers. Nevertheless, their roots are still important influences on the material they choose and how they perform it.

I don't think you have anything to apologize for--that's a pretty great lineup you've booked!

best
W-O