I was unsure about the foam mats after converting to SIMs myself but when I sent DS off to camp with one, he was absolutely fine and I can see why on cub and scout camps you wouldn't want the hassle of damaged SIMs. My DS will sleep anywhere. Try the kids on foam mats practice camping on the living room floor.
My DS has never had a problem with tent zips and finding his way out, whether shown or not! Don't think he's needed a midnight wee though. Mine's a wiggler and the camp bed is a better idea, failing that a SIM or foam mat which he just tends to roll off. Air beds and boys = trampolines! Unless you have very gentle boys are are short on space, I'd go for the foam mats over the SIMs, DS has torn his SIM twice, probably because of mucking about in the tent with other boys.
We tried air beds when we first started camping but went through loads because the kids used to abuse them as trampolines, we now have the cheap SIMs and sling an old duvet on the top for extra padding and warmth, they just snuggle down together. Your setup sounds fine as a start, my kids are usually so exhausted come bedtime that midnight wees never happen, and they've managed mummy sleeping bags from that age with no problems.
I have camped loads (cub scout leader) DH rarely. The boys have never been. I have various tents but thought we would risk a weekend in the 2 podded tent. One pod at each end and central 'living' space. Would you put the kids in the same pod - worried about managing the zip for midnight wees, and what is best for them to sleep on? I have a double and 2 single air beds and a variety of camp beds ranging from the low fisherman type ones to the higher type. My thoughs are single air beds(threaded together so they dont fall down the gap) in the same pod. Also I will need to get sleeping bags. Thoughts here too. I have mummy bags, would square ones be easier for them to get out of?