Definitely. I'd put an ad in craigslist for someone with perfect dental health to enroll in a "research test" in which their tongue is scraped 3x daily and kept in fridge for daily collection. (will it survive that?) Would pay them of course not sure how much would be necessary.
So gross though I don't know if I could do it without puking.
No. it won't survive refrigeration.
Cold kills bacteria, I wouldn't risk it.
People will do anything for money, but having a stranger is risky af. You'd need to pay for testing HIV, Hepatitis etc. Starts to get complicated and expensive.
But anyway, see if this works first, hey?