Also, can I have it without mayo? And it says they prefer you order a burger, does that mean I definitely shouldn't order a hot dog?
Yes. Allow a minimum of 20 minutes for this: the wait for your food, then required to wait 10 minutes for a "check back" -- which, in reality, because of short-staffing, currently doesn't happen. But you still have to wait the 10 minutes. And don't take a single bite until you've taken the requisite photos!
I would LOVE to order a chili dog, but theirs have cheese. I really can't tell from the guidelines if I can order it without cheese and with onions. And mustard!!!
PS - be sure to know before you get there exactly what to do if you get no response after pushing the red button, and what to do if drive-in is closed. If you don't get these right, your shop will be disallowed.