Option #4 sounds good, if it weren't for $$.
As for the different ceiling heights...that's not really the problem. It's not that the floor drops height over distance. It's just lumpy...like that half eaten bowl of oatmeal that you left in the sink overnight. If I were lay a piece of plywood flat on it, it could double as a crude surfing simulator.
I think that Option #1 is the most appealing to me right now on a number of levels. It's just a matter of cost. There seems to be floor leveling stuff that you just pour and a day later you can walk on it.