Whats a good moveset for an all out attacking Gengar?

Okay I really need help because his special movepool is so large I cant even choose all four. And no status as this is an all out attacking gengar. These are my restrictions though(Gen 4)
1)No hidden power
2)No mixed gengar meaning no physical attacks like focus punch
3)No 2 moves of the same type

This is my moves for gengar so far and wont change those moves no matte what.

-Shadow ball
-Focus blast
-???
-???

I recommend Thunderbolt and (You're gonna hate this, but) Hidden Power Ice.
You could use Energy Ball or a similar move, but at the same time you should really ask some of the breeders to work on getting you one with HP Ice. If you weren't aware (or just haven't bothered to think about it) electric and ice have neutral coverage to nearly every pokemon.

Okay I was thinking thunderbolt wasnt needed since it only has 2 type coverages but I guess its a good move since everyones recommending it and its necessary to take out bulky waters.(Had thunderbolt in my gengar moveset before but had doubts on it but I guess Im putting it back again) Also actually I decided to put willowisp instead of an all out attacker gengar because I figured most of my team is pretty frail and could cripple physical sweepers.

Hey also, since you seem to answer the question quickly, can you answer my other question too?

What was your other question?