Haven't heard any issue with the negative cable touch ground. Seems most issues are letting the positive touch ground when changing or removing the aux battery: blow a fuse in the high amp array, on the side of the battery. You can disconnect the aux negative cable to just charge it, and test...
If there a bunch of random codes , loss of CANBUS, etc. It's a good possibility it's the green canbus connection block (aka Star connector) in the glovebox is the issue. Had the same couldn't shut off issue with a bunch of codes.
I bought a set of four of these wheels. Want to get a fifth for the spare. Dealership has no clue about the gloss black wheel. Part number says it grey with polished edges.