I can't be Premier specific but here's answers for our 2014 Laredo which I suspect are similar...
1. Cable vs Satellite, two inputs. Cable routes to both TV locations and is the same cable as the TV antenna. The pre-amplifier must be switched off. Satellite routes to it's own connector behind the main TV only. Bedroom TV has a feed from behind the main TV that can be un-jumpered and changed to accommodate feeding it from a dish receiver stationed at the main TV.
2. On ours there's three "zones". Two speakers over the TV area, two over the kitchen, two outside. "A", "B" and "C" buttons on the stereo control which are on. Any combination of none or all.
3. The TV audio for the rear TV is wired into the stereo. A bedroom TV would have to use it's own speakers, there are none mounted in the ceiling in the bedroom and no cabling run from the stereo to that area.
4. There are Bluetooth adapters for cars that will work fine. I believe the stereos typically have an "aux" input jack on the front or RCA inputs on the rear these days.
5. We are wired for an outdoor TV and I see no audio, component video, or HDMI pre-wired to that location. Just power and one 75 ohm video cable.
6. I've read that they're changing constantly here and elsewhere. Even in the same model year. The general design is usually similar but best to get the model right off the unit itself.
7. They can't on our system.
Of course take all with a grain of salt since it's not the same trailer, but I suspect from having looked at a number of them that they're similar. And if model numbers are different, the general setup will be about the same.
Also if you're a music aficionado, the cheap stock speakers are the very essence of mediocre-sounding. You'll want to talk to an automotive stereo shop about upgrading them, unless your music type works well with muddy highs, mostly mid-range, and virtually no bass. We have some other stuff we want to do to the trailer first, but sooner or later it will annoy me enough that they'll be upgraded.
Along with that upgrade, see another recent post about the outdoor speakers not really having a proper waterproof or insulated barrier around them. I haven't had mine apart yet, but from the other thread's photos, I expect to find just a hole with a speaker stuffed in it and a massive air leak around it. That will also be easily fixed with appropriate stuff from an automotive stereo shop or online automotive stereo parts place.
Pilot for fun, Computer geek for a living, and happy 5er owner who wants more time to go play in the camper!