First of all, welcome to the 5th wheel world. Great times are ahead. Can't see any of your photos though because of the Photobucket thing. I'll offer suggestions for some of your questions.
1. Assuming the fridge is an RV type, you'll be better off running it on propane. AC will be out unless you bring along a whole other trailer just for the batteries. Better option would be to use a good quiet inverter type generator. Yamaha & Honda are the gold standard, but there are other brands that are cheaper with similar performance, just not the quality or long life.
4. We have yet to find a pull out couch that is comfortable for sleeping 2. Doesn't mean they aren't out there though. A good blow up mattress with a foam topper can be pretty comfortable.
5. Not much point to beefing up the lock as there are many other easy ways to break into an RV. Sad but true.