First thing, You will fair better with a single item in a post so the answers don't get lost in the long posts.
1. Slide issue: The slides do creak and squeak as they move. Some more than others, if they do a slight lifting as they come in. Some squeaking comes from the rubber seals sliding along the slide. If you look under the slide you will see a number of rollers that carry the weight. If they are dry, it adds to the noise. I've been told by factory technicians that they spray them with Automatic Transmission Fluid (ATF) as it does not attract as much dirt as many other lubricants.
2: Water on the roof of the slide: several things cause this accumulation, rain and AC condensation are leading causes. With the slides open, and prior to closing I manually tilt the coach to allow this to run off before closing the slides. Remember to relevel the coach prior to closing the slides
If a lot of water comes off when doing the above we take a couple towels and put them on top of the slide once closed to catch any leftover so we don't get the rude bath. Leave yourself a note to remove towels before opening the slides, don't ask why I tell you that:)
3: Hot Water: a couple known issues, if the outdoor shower valves are not closed, you will get a colder shower as it allows more cold to mix. Second major issue is on demand water heaters require a minimum flow rate to stay heating. I've experienced the fact that while my wife loves steam coming out of the shower, I prefer it a bit cooler. The balance is to have it hot enough to keep the heater working, VS cool enough to not be too hot for me is very delicate. If I shift the knob just a little too cool not enough water is flowing through the hot water heater to keep it working.
4: Water pump: The water pumps in a coach will not deliver the same pressure we come to expect at home or when connected to city water. I'm sure for enough money and the addition of a pressure tank someone could work out a solution, but that is not what comes standard. The technicians comment that the pump is junk, may have really been his opinion that pumps in general do not give you pressure like he thinks you should get, not that the brand pump is really junk.
Hope this helps, and hope you enjoy your new coach.