The drivers must show a paper copy of their forms to enter through the Park Kiosk where we pay to enter the park. This is in addition to the EPL paying. A copy of the form on the driver's phone is not sufficient, they must have it printed out. Your drivers could possibly print their form at the hotel prior to Grand Canyon day if they don't have a paper copy. The ranger let the driver's phone copy pass this time, but he wasn't going to let us enter.
Also, the restrooms at Desert View Watchtower are currently closed. They have portable restrooms if need be. My group didn't want to use the portables, so we found a nice service station about 30 min heading toward Flagstaff for a restroom stop.
The South rim trails are open, but due to heavy snowfall, some of the trails are snow covered and icy. For anyone visiting soon, you may want to avoid the walk through the forest to Park Headquarters. We avoided that and had the coach pick us up before that area. There are many areas the coach can drop for rim overlook views.