You cannot "not inhale completely" anything. Either you inhale it - aloow it to enter the lungs - or you don't.
If you refer to letting the smoke simply rest in the mouth before releasing it, then yes, this can quite easily be detected, although metabolite traces will not be at levels as high as if breathed properly.
Yes
If the marijuana was inhaled it stays in your body for 30 days.
Marijuana can be detected in saliva for up to 30 days.
Yes
Yes, marijuana is detected in your blood stream system.
Yes.
30 days.
Yes
20 minutes later
nope
if you're implying marijuana, yes, it can be detected in a urinalysis.
Marijuana is harmful when inhaled. No matter what you are lighting it with.