If your goal is to possess your opponent a lot, I don't think you went about it very well. Specifically, University contributes absolutely nothing to gaining possession. It's a handsize reducer that gives you useless +actions and let's you gain actions that don't help you. You gained a billion worker's villagers that were useless. You ambassadored away all your money (feeding his PStones). You didn't curse your opponent until T15.
For playing a possession strat, 5/2 is a terrible opening here. I have no idea if this is right or not, but I would think about opening potion or even silver instead of ambassador, which is both dangerous and not helpful to your plan. Until I can buy possession, my only goals are alchemists, money, and warehouses as needed depending on how much junk he throws at me. Probably add 1 amb in there eventually if it looks safe (or lots of ambs to give to your opponent). Once you get a couple possessions, load up on potions, warehouses, and villages to play more possessions.