u/MaterialisticSaint96

I want to visit Grand Canyon South Rim with 3 non-resident family members (2 adults, 1 child). I have a valid US drivers license (on a valid US work visa). I would like to have some clarity on non-resident fees. I think I'll be eligible for the one-time standard resident pass of $35 and the 10 year old child should be exempt from any entrance fees. I have 2 options:

1. Day tour via bus tour companies: Do the park officials check residency status of each person on the bus and collected the $100 at the entrance or do we have to pay the $100 to the bus tour operator and they pay it to the park officials at the entrance or how does this work?
2. I'm also thinking that if I'm eligible for a standard pass, I might keep my rental car for another day or two and get a standard pass for 1 private vehicle. In this case, would the park officials ask for each person's residency status and charge $100 or are they included as a part of the same car?