Are you allowed to have barbecues and picnics there and does the park open and close at a certain time?

Yes! You Can BBQ There.

Yes there are grills and picnic tables all over the park, and I am pretty sure it opens a dawn and closes at dusk!

I liked it a lot, there are whips. Very well organized, you must collect the garbage and carry it. , it is a beautiful and familiar place. They sell hamburgers, hot dogs, sodas. I recommend it. The lake is beautiful. A whole landscape.

Park typically is open at 8 AM. Depends what park of the park you go to though. Closes at dusk. (Approx 8pm). Theres grills all over the place, you just need to bring charcoal. Theres pavillions you can rent for events or people can just gather where ever. The parks gigantic.

Yes you can have bbq and picnics,some area u have to rent out for occasions but down in park by water and playground u can find a spot and grills are right there and have your bbq and picnic,hrs are usually 8:30-5:00 but once your in u can stay past that