I can really sympathise with you wanting someone else to tell you what to do for the best! My cancer experience was several years ago, I spent months researching and getting second opinions trying to find support for doing what my instincts were telling me (doctors were advising hysterectomy or at least radical removal of my cervix, my instincts said that the large cone biopsy I'd had was enough...I was right!). But I never did find a doctor who could definitively say "this is what you should do in this situation" that I agreed with! It was a real personal growth experience for me, learning that I was the only one who could take responsibility for decisions about my body. Glad I made the right call as I've had another baby since then and am now 30 weeks pg with yet another!
Anyway, your situation is quite complex - you just don't know how a vaginal birth will go and whether more damage will be caused than with a c/s. Do you think there's anything you could do to soften the scar tissue prior to birth? Anything from oil to medication of some sort? I guess the effects of a c/s seem more predictable, but there are unknown risks there too, from wound infection to adhesions to who knows what?
It's certainly possible that even if your scarred skin did split during birth that it would heal well without stitches (e.g. torn perineums heal well within days unless the muscle is torn, salt water works wonders) and there wouldn't really be long term effects, but it's not predictable, maybe a water birth would help as it helps the tissues soften...
As you can tell I'm a bit of a natural birth fan so don't let me tell you what to do, I'm just concerned that c/s seems like the 'safe' option but actually there doesn't seem to be any literature that suggests c/s in this situation, and in general vaginal birth is better for both you and baby. I hope you can get some sensible advice from a professional (although I wouldn't hold my breath if I were you, I had some ridiculous advice from a top London gyn with my situation!) but at the end of the day you just have to go with whichever set of risks you are more comfortable with.
God I've rambled on, hope this is some help to you and you make a decision that you are happy with, it doesn't matter what other people tell you you should do.
xx