I'm pretty sure #1 would not be allowed. But you should call the wilderness permit number and ask. I'm thinking that if the not-confident leader started the hike and turned back, all the others could continue on. You should have multiple copies of the original permit. There isn't a rule that groups must stick together, (but splitting up can lead to other (safety) issues.)
#2: that plan would be ok. But starting at 10 pm can lead to being a zombie on the way back due to lack of sleep.
#3: No idea. Many hikers never get checked, but that's random.
