Is it a first come first serve kinda place if a few of us were to have like a get together with a picnic or do I have to rent a space?

Yes and no. U'll probably want to rent a spot if it's anything other than Few people..it gets busy.

I believe you have to rent a space

If you want a covered area those are on a reservation and pay system, if you are in one of those areas without a reservation you are taking a risk that someone who has a reservation will kick you out.

Sorry I have no idea. Call parks and recreations of South Daytona or Port orange.