by the thing the knobs attach to, do you mean a control plate like on a telecaster?
it wont fit on a carve top les paul. or do you mean potentiometers?
Get the book Build your Electric Guitar by melvyn Hiscock, It will help.
check to make sure the neck will fit the body.
soldering is not a big deal. a solder gun can be bought for 15 bucks, and soldering is easy.
As for humbuckers, It depends on the type of music you will be playing.
Id suggest passive, not active.
If money is no object, Id suggest using a Seymour Duncan Jb in the bridge and a 59 or jazz in the neck. thats a really versitile combination.
If money is really no object, use prs pickups
However, Money is usually a factor, so Id suggest buying mighty mite or bill lawrence, or kent armstrong pickups.
Just dont buy one of those dimarzio dual sound pickups. Originally they were called super-distiortions, but after a few years of popularity, people realized they really sounded terrible when clean, and pretty lifeless even when distorted. (people can be pretty stupid, they should have realized it earlier.) So Dimarzio renamed them "dual sound" and now uses 4 conductor wiring instead of 2. thats the only real difference.