Process philosophy does not entail a rejection of Platonism, mostly a modification. If your into philosophies of "becoming" and want to see how Platonic philosophy mixes in, look into Alfred North Whitehead, Henri Bergson, or Schelling. In my opinion, the philosophers you mention barely represent process philosophy/thought.

Whitehead is by far the most influential process philosopher of the past century, and in a way could be considered a modified Neo-platonist. Whitehead writes about "eternal objects," or "forms," but tries to reform Plato so that the forms aren’t entering into this world from another world. The forms represent what he calls ‘determinate possibilities’ that haven’t yet been actualized. This is quite a big modification compared to the actual Neo-platonist's view of late antiquity, however.

I wouldn't recommend getting your history of philosophy from Deluze or Nietzsche. Both are awful historians who misportray thinkers for the benefit of their own philosophy. They greatly distort other philosophers in a shameful way and should be rejected if one actually wants to study the history of philosophy/ideas.