Question re Multiple Rooms Under BRP and re Passholder ID

[Piglette]

If you are booking more than one room under the BRP, do you have to book both rooms for the same number of nights? We would like to book one room for 6 nights, and the other only for 5.

Also, if our friends are meeting us (and using the 2nd room), do I (as the passholder) have to be there when they check in? Or can I go to the front desk later and show my pass if there's any question? We will be at the parks when they arrive, and don't want to come back for their check-in.

Thanks!