G'day, Lascaris.
A lot of the answers will depend upon what equipment you buy. I've shown some examples of my equipment in the links and you should be able to find equivalents. In general:
1. Yes, but you'll need either very good air flow (ie all windows open) or, recommended, a spray booth (eg link).
2. and 3. An air tank will give you better spray performance (no pulsing of the spray) and they can be very quiet (see link). Choose one that comes with a water-trap regulator.
4. A couple of days of practice using your preferred paint (old cardboard boxes work well for a practice surface) will let you work out air pressures, thinning, how to get an even coat and how far away to hold the brush. After that it depends on what you want to do. For undercoating and main colours on figures or vehicles you'll be right to go. For doing cam patterns on 10mm vehicles and similar then you'll need day or two of practice, doing just that on cardboard or sheet plastic, before you'll get results close to what you want.
5. I have both. For main colours on figures and vehicles, and for undercoating, the single-action, bottom feed (a Badger 350 link) works really well and is much less fiddly to use and clean. For really fine work then a dual-action, gravity feed is better. I have the AB-134BK (link), which can easily do three-colour cam on 10mm modern AFV. But dual-action take a lot of practice, as each one is different, and I still swear frequently when using it.
Best advice I can give is to find a local scale modelling club and go and talk to them. Most of them have teaching days where you can learn to use your gear. They will also be ready to give good advice for maintaining and using your kit, where the best prices can be found, and useful techniques like "splattering" (great for weathering vehicles).
Cheers.
