They're more likely C-22 negatives. I'd expect there to be dye fading, which would be very hard to correct with filters, there will be crossover problems. (Each dye has faded a different amount.) I think this is a case where digital will provide better results. You don't need a super high-resolution scanner, 127 ans 126 Instamatic cameras weren't generally very sharp optically.
A pro lab that uses something better than a Noritsu or Fuji minilab scanner shouldn't be fazed by them at all. It won't be cheap. For instance, Dorian Color Lab in Arlington MA uses an Imacon Flextight scanner, scanning odd negative sizes with it is no challenge.