Re: tile adhesive
Are you stripping out all the second layer of self-stick tile or just the loose/missing pieces? If you're only removing what's loose, then you'll need to fill the holes left by the missing tile. The easiest means would be to purchase more self stick tile, doable but more work would be to float those low areas with leveling compound. If you're stripping out all the second layer, don't worry about the sticky and just lay down your vapor barrier.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!