I think you have a good list and have it decked out pretty good! Fantastic fan in bath - yes. Large entry grab handle by the exterior bathoom door - yes, especially handy for the little ones. I'd skip the 12 gallon water heater and install this shower instead. ://www.campingworld.com/shopping/item/body-spa-rv-shower-kit-white/68324
We got the Serta matress upgrade and put 3" memory foam on it anyway so you could skip the upgrade and just go memory foam.
Reconsider the double pane windows. You mention it gets hot in 'bama. Well the double pane windows do help keep it cooler inside.
We got the fireplace but we're up nort' in a cooler climate and it helps out in spring and fall. Down in 'Bama I'd forget about it.
12 cf fridge - Do you lose the counter/cabinet space to make it fit? Gotta decide which is more important to your camping style. Me, I'd prefer to keep the counter/cabinet space.
Not on your list above but consider either you or the dealer installing a cover like the MaxxAir II over bath roof vent. Also consider a surge protector like this Progressive Industries 50 Amp RV Electrical Management System w Remote Display - Hardwire from tweetys.com
. I know it looks expensive but considering what it would cost to replace all your onboard electronics, tv, 2 AC units, boards on fridge, furnace, water heater, etc it's cheap insurance.