He'll easily fit a small hide if he is that young. Gina who is an Aug 2016 snake fits a large RBI hide with lots of room to spare. And a lot of the time since I've given all the little snakes 2 bags of cypress, they have been sitting outside the hides buried under the damp cypress all stretched out.
As for PAM, i personally dont like to use chemicals on my snakes so my advice would be to just spray PAM on a rag outside and then just wipe down the outside of the cages and any cords and table legs/table tops that the cages sit on or anywhere that mites could get into the cage, especially around the vent holes and door openings.
And for the QT cage, i would spray the PAM now. That will give it plenty of time to dry before the snake arrives. Although honestly, i kind of broke the rule and didnt QT Gina when i got her lol. I know you should but i have been rather sloppy about QTing my snakes recently. I just had faith in the breeders i got from as they were big players in the game who have a big reputation to hold up so i couldnt imagine them taking chances with tarnishing it. And yes, i know that is still no excuse lol.