The point buy thing aside - my group doesn't do point buy, we just roll for random stats - and the hybrid/occult classes (understandable on the occult classes, the mythic paths do not fit them), your first mistake with his character was allowing his stats to be so hugely and wildly different from the rest of the group, even if he was using that race? It sounds like he padded the points a bit more than you can before even taking mythic traits and abilities. The arguing and bad behavior, refuse to pay him attention, tell your decisions to the group as a whole and stick by them. If he has a fit, stop running, ask him to leave as he's not letting anyone have fun when he acts like that. Now, that's just for his behavior in general, but adding in the cheating with the abusiveness, either you work around it, give him secret penalties and make things harder for him to steamroll, or you tell him that you know he's doing it and that it is not welcome in your group, tell, do not ask, him not to come back.
Now, you can offer him a second chance but if you do, don't do more than one. And lay down all the ground rules as a group and in the open so he cannot claim you did not say that.