I cave in the AV Holloch, which is the same suit with a slightly shorter back length. Most of my trips are in cool to cold alpine caves in BC. Usually some water about - a bit splashy you could say.
1. Cordura/packcloth type fabric. W/P coating. Polyamide = Nylon AFAIK.
2. The fabric holds some water. When I wash it it takes a few hours to dry, but I wouldn't say it's a huge amount of water.
3. Holds some mud, but not excessive, IMO. I have never used a PVC suit, and imagine they would be much better in this regard. I have a muddy dig going, and the suit certainly weighs more after that, but it rinses off fine.
Overall I like the suit. I have worn out the knees and the butt, which I rebuilt last fall, but I will be buying a new one this Spring and keeping the old one for dig trips. The front of the legs are doubled fabric as are the elbows and butt. The way they are designed, once the first layer gets a hole, mud/water etc can get in with no easy way out, so that is a bit annoying. The Velcro closure has started to be unreliable, but that was about the same time the fabric has worn out, so seems reasonable.
Where are you getting yours, may I ask? I was going to order from Starless River again, but if there is a good N American source, I would be happy to know.