NO. -You buy special drill tipped screws for it at the same places you get steel studs.
Vapour barrier is directly onto studs.
If is an exterior wall, insulation, otherwise bare studs walls are fine.
There is no drywall glue. -If you are referring to mud (drywall compound), you scrape the lumps off at the end of each day and then wash your clothes. It always comes off.
It will, but PL Premium is better
If you drywall on 16" on-centre studs, with sheet length perpendicular to the studs, and screw the two outside length edges at 6" spacing (as it should be) and the two interior studs at 12" spacing, the answer is 48 drywall screws per 4'x8' sheet.
It shouldn't be a problem. The glue is water based and the mud should adhere to it.
That is the thickness of the studs, -the inside of the wall.
American Builder - 2004 Island Pond Drywall Studs 3-21 was released on: USA: 25 May 2006
American Builder - 2004 Liberty Way Studs and Drywall 4-73 was released on: USA: 15 October 2007
everything including 5/8 drywall only requires 1 1/4 length drywall screws. you put them in 16 inches apart on the studs and in the center the same distance apart.
Your question is vague. - Usually plumbing pipe fitting is between studs in the walls. To fit new pipes, find studs with a 'studfinder' then cut down the centre of studs to remove drywall. Install pipe, then refit with new drywall on the 3/4 " of stud each side.