Holy Guard Unhappy Girl deck will neuter him. If you get 2 Unhappy Girls fast, it's game. Summon only 2 to prevent field clog in the final turn. Pack 3 Riryoku Field to counter Order To Charge. Use Abyssal Designator on the final turn to remove Kuriboh. Don't worry about Megarock Dragon, he cannot special summon it once he have clogged his field with Unhappy-locked monsters, as long as you don't destroy any of his monster. The only possible problem is A Feint Plan, if he gets that card early.
No. Once you attack the face down Guardian Sphinx with Unhappy Girl, he cannot change the battle position, thus unable to activate its effect that activates by flip summoning.
But once your Unhappy Girls have finished locking all his monsters, A Feint Plan will no longer be a problem. He only have a copy of that, so it's just a small probability and you don't need to thoroughly prepare for it. Probably need to pack extra cards against Order to Charge though.
This is what I made for the first dry run. Can definitely be improved. BEUD in the extra deck. Don't forget to add Abyssal Designator. Econ, etaqua, anubis, and kuriboh can be replaced and not needed, maybe with cards that can boost draw power.