I've the MRC advanced on the layout with 2 wireless and 2 advanced and 2 express handheld works great . Then I have the MRC express with an advanced handheld on the work-bench.as to the other systems I have no idea.
I use TCS decoders almost exclusively love there no fault warranty. Most if not all decoders work with any system.I would definitely solder the track feeders better connections better off you are with the DCC signal!!:D
Don't know
Don't know fer sure but could you take some fine sandpaper and lightly scuff the surface first or put a thin coat of plaster/drywall compound first?