On the gaps in the doors...foil is a good choice and temporary since the Q is borrowed...that way the owner won't have to relearn the Q after you are done repairing it...
I would drape foil over them and then a towel or blanket on top to hold it in place...for the fire box you can stuff foil in the gap too, then close the door on it to help restrict the air in....good luck...that thing looks like as beast...
"Before the end of this thread, someone will tell you to build a UDS"...Nostradamus
Lang 36 Patio - Kamado BigJoe
30" Gasser(Dock Box)