I know my PIN code is for me. If I am on the reservation, would I need to be there at check in?
I would suggest calling ahead and asking to be sure. Technically you could book/pay for a vacation for someone but not be the one staying in the room. I always book my parents vacation for them and all their info comes through me and my name is on the reservation even though their names are on the room and they are the ones checking in.
To my knowledge, PIN codes are usable only by the person that received them.
I’m not sure if you can transfer your reservation to someone else and the fact that that reservation is secured by either a cash or credit card deposit might create a grey area.