Is a single person in a car still $20 ?

Yes $20 per vehicle until it is safe enough again to buy your tickets upon entry. But $20 is still a good deal even for or person for the double feature and we'll worth it. Great projection

You can have up to 6 in a single vehicle for 20 dollars curenty

Yes

I assume so, seeing as I was there 2 Sundays ago. It was my first time being there, to be honest.

Yes, the ticket is per car, up to I believe 6 people.