Can you Reserve The Gazebo. Just to ensure You can hold a function like a birthday party without the fear of having to do it in the hot sun bcuz some buttheads wants to go Hold it up so they can "just chill"?

Call the park Dept. They can answer your question. But I'm sure you could.

Yes you can reserve it for a fee it was like $100 for 6 hours or there was a couple hour option for a smaller fee. You need to call the parks department to reserve and they will send you a confirmation email

Why don't you call city Park department...

Best way to get that answered is to call the city.