1. People need to stop making remarks about JKR's ego and character from information that is rumors and people's assumptions. It's fine to speculate and post our opinions, but you can't say things like whether she has a big ego or not. You're not there in meetings to know JKR's demands or her attitude towards anything. Also, she didn't give up the right to anything. She and WB gave Universal license to use the HP characters, locations, etc. and make an attraction out of it. They can make new parks and as many expansions as they want. Universal probably has exclusive rights to use HP in theme park environments, so any other Potter theme park related things will probably only happen at Universal, but anything can happen within whatever parameters they agreed upon. Even if they decide to build a whole new park somewhere else.
3. Again, what attitude? Did witness any attitude from JKR? It's not fair to say things like that. And Universal needs JRK, not the other way around. JKR is a gazillionaire and I'm pretty sure she was seeked out by theme parks, not the other way around. She is the one being approached for her product (HP), which Universal wants to use to increase their business. JKR (and lets not forget WB who also own a bunch of the rights to HP) have the power and influence to request whatever changes they want because it's their product that Universal is borrowing. And that's not to say they are actually demanding anything or having an attitude. I'm sure that Universal is going to JKR and asking for her opinions and guidance, not just because she owns the thing, but because they want her input. And she's in all her right to give any opinions, the same way Universal can take them into consideration or not.
I respect your opinions as far as having your preferences, but no one of us can go speaking about a person's character when we really have no clue about it.