Congrats on your MKS. I have a 2009, as well. When people advise against getting a first model year car - these are usually the problems that seem to happen. Gotta love used cars, right?
Your radio antenna is part of the rear window. I'm not sure how it is wired in, but if you were cleaning your back window or messing with something on the rear shelf - you could have damaged or disconnected your antenna. The internal antenna pick-up or something inside your radio could have also crapped out. I had a 2003 Town car that I had to send in the radio to be repaired when the radio turned to static.
I have also had the rear upper hand grips/grab bars ripped off of my MKS. You can find a screw with bigger/thicker threads to try and screw it back on, but in my experience - it will eventually rip out again - fat friend or not.
Not sure about he console armrest - leather issue. Mine just gets dirty from use - but that is just a surface dirt that wipes right off.