No
Since it is Easter the parks will be busy. You don't need a reservation but if you want to guarantee a table you can either have someone get there early to get a table or make a reservation. Or bring your own table and chairs and blankets, then you can sit anywhere you want in the park.
You shouldn't unless it is a huge celebration. Normally it is first come.. first serve. So if it's just a regular BBQ outing you should be good from my experience. Hope this helps.
Thanks! Your answer is awaiting moderation.