I looked up capacities for a 2009 Suburban 1500 and it says 5100-5400 pounds, so you'd be exceeding your capacity with that rig by quite a bit.
WD hitches are set up for each individual vehicle as to height and number of chain links used so it would be a pain to pull it with 2 different tow vehicles even if the suburban was capable. You'd need an extra receiver head/assembly for the suburban, or if the dodge one had enough adjustment for height you'd have to take it apart and set it to a different height. It would just be bothersome, I wouldn't want to go through it every time.
I try not to store much in the back end of my trailers since that's where the most bounce is. I also don't think it's a good idea to lighten your tongue weight, you need a good percentage of tongue weight to prevent fish tailing. Right now your tongue weight looks to be almost 15% and that's a good number.
I have one sway control bar on my sunset trail 250rb, trailer goes 5700 empty so I'm probably pulling it at 6500 pounds or so, and it does ok. I should probably have 2 but have got by with one. Looks like this:
I have 2 of these on my 3001W windjammer because it's heavier and 34.5 ft long and at the limits of my Silverado.