Can you bring your own portable bbq grill? If so does it have to be propane or can it be charcoal?

As far as I know you can take your own but the Everett parks webpage is helpful and updated with info

I have never been told one or the other I would bring whatever you like better because I have seen charcoal cans to dump your ashes in and I have seen people with propane barbecuing so whatever suits your fancy I say.

Yes. And I think propane or charcoal

Yes

Yes you can