It certainly is.
Do not think so. Do not see great apes interbreeding with monkeys or chimps. What the books and other documents that I have read say is they cannot believe that there were more than one species of upright walkers that arose in more than one place. I think interbreeding requires the same ancestors and I do not believe that Neanderthals were from the same species that we are from. But then I might be wrong since it is just my opinion. But if I were a part of the immigrants into Europe I would have made sure that no species were left that would have been competitive with my food gathering.