If the bark is slipping on the stock T buds have a good chance of taking. The real key is that the bud be cleanly and clearly under both flaps of the T and flat against the cambium of the stock. Do that and the bud should heal in.
We are at that point where forcing the buds might be an issue. I’d probably favor trying to force any buds that look good after two weeks. My experience of holding T buds over winter isn’t good. And if you are going to wait that long to force the bud you might as well just regraft in spring.
You might also want to protect any exposed stock or bud and any subsequent growth from the worst of the heat if possible. Paper bag or tinfoil.