I have been giving alot of thought into how all three versions of the planet of the apes films sereis could be integrated into a single timline
here are a few details
Cornelius and Zira did not arrive on earth in the past but rather onto ashlar
Oberon was launched by humans trying to escape earth and simply pretend that the occurances on earth were not happening, thus their goal was to find a new world and live in denial that it wasnt earth. Mimicking the old world as best they could
of course its all very silly, but if someone thinks its an interesting idea I may make a timeline up for it for kicks :P