I've never tried to do this but, seeing as nobody else has posted, here's my thoughts, FWIW. a dowel of the same kind of wood might sort out the hole in the heel, and it would be noticeable but not in-your-face noticeable. The hole in the end-block - you could pop a mother-of-pearl inlay in there, which might look okay. Or you could make a wide inlay strip, remove the wood around the hole and put in the new inlay strip. However, your endblock inlay strip would then be wider than your centre strip, if you have one. Also, you wouldn't want to remove too much material. The sides need a certain area of endblock to glue to.