Generally speaking Saliva tests are less accurate than urine tests and yes...Im not quite sure why you would be concerned if you can pass a urine test. Alcohol stays in your mouth until it evaporates...
No,
saliva drug tests prime detection range for THC ( cannabis) is normally up to 48 h. Urine - 2-7 days (single use) , up to 10-12 weeks (prolonged use).
Clean your system. There are things you can do to rid the body of THC fast: speeding up your metabolism , eating a lot red meat , taking a fiber additive ,taking vitamin b-12 , drinking a lot of...