It does depend on how long the cherries have been in there, but once you take the beer off the cherries it is going to oxidize very quickly. I'm talking minutes, and it's going to start smelling like vomit very quickly ...... I don't think you are going to want to re-pitch on it.
If you want to salvage some of the cake/bugs, you could strain the cake/fruit through something like a paint straining bag; use the liquid and dump the solids.
Yes, you will probably want to add some fresh yeast.