So if for example, the GC hired a painter and it rained for 2 weeks, I wouldn't reduce the amount because no sub-contractor could have done it.

So painter.....someone to replace the water heater and smaller stuff. 

First I'll meet with him and make sure I'm comfortable with him, his background, his approach.I'll also ask him for any referrals (people he knows and trusts) of professionals who can help me fix distressed homes (painters, plumbers, electricians, etc.).

It is costing too much fully painting in 1 or 2 years as I hire painters. 

None of the painters I know will use paint from there.

Most painters, carpet installers, plumbers, electricians, roofers will and can show you a materials list and ask for some type of payment up front.

If you're going to paint the cabinets, consider getting a painter to shoot them with enamel.

A small handyman/painter could take care if it.

As for the contractors prices , I like to get at least 3 but if it's a house you haven't bought yet and time is a issue then call a couple drywall guys and ask for a best guess then same with painter ..ect..

If you can get a good painter/ drywall finisher to work for you and teach you for a week, you will learn so much from these guys just by hiring someone really good for a week or so.