I had a free flap elevation from both my lower leg and my wrist. The tissue from my leg was removed, and they rejected it for implantation because they couldn't get it to perfuse properly.

They then went with the flap from my wrist to rebuild the lining of my mouth. The opening in my wrist was covered over with a skin graft from my thigh as well. You mentioned that the graft to your cheek fell off for the most part; I believe that is pretty normal...the grafted tissue (at least the uppermost layers) sluffs off a few weeks after grafting.

By that time, the tissue growth is well underway, so it's well on the way to healing.

I think the surgeons have to have a plan "A", a backup plan "B", and maybe even a plan "C".

It really makes a lot of sense. If the ideal outcome isn't possible (as in my case) there has to be an alternative to doing nothing.

Even though they had done an angio-CT of the leg they were going to use for donor tissue, they still couldn't know for certain if the blood supply was adequate until surgery had begun.

I guess I choose to look at it a bit differently; Perhaps the flap from the hard palate would have been less invasive overall if it had worked. It would be something that you have every right to ask the Doctor about, though. You're entitled to know after all
Wayne