No payload isn't an issue with the smaller camper and srw, but since your prescribed list of requirements is so detailed and uhhhhhh unique and you are scrutinizing to the finest detail, here's some more to think about.
Didn't realize you'd be true ft. Thought you were doing 5 months at home. Ultralight TTs are not best suited for full timing. Amenities, quality, insulation can be a lot better for long term use in RVs designed for it. Pulling a big heavy TT with your fave setup would suck.
You keep comparing to your default setup being a plush Class A. It IS better suited for ft and are you sure a mismatch of minimal type campers is what you want to live in ft? Make sure your wife isn't secretly hoping for the triple slide pusher with a full residential bath, dishwasher, washer/dryer, etc.......cause mine would be!!
And I'd go buy a new 3500 long bed dually. Or my personal fave, Mega cab dually! Torontos no different than any other city I've been to. RVs aren't meant to go downtown and a dually is a biatch too. How many days a year you parking downtown or going to your special church that doesn't allow campers or dooleys vs how many days are you going to be loaded up livin the dream? Better be more of the latter. I'd take a b!tch to park over being right at capacity if I was camping more than the 3x a year I get to go!
Then just go buy a camper and TT and let er rip. Could pick up a couple nice used ones cheaper and quick with some cash and go see how you like it before going all custom on everything. Be easy to upgrade especially since you're packing 2 houses with you. Live in whichever one ain't getting traded in while making the swap!