I am starting on my bathroom remodel, and am putting in 12 x 12 ceramic tile. The floor is linoleum on top of vinyl tile, I am ripping up the linoleum but the vinyl doesn't want to come up. Is it all right to leave it? I am planning to use 1/4 Hardiboard. Do I need to level the floor or is this going to be all right? Thanks.

You really should remove the vinyl tile too. There should be a thin underlayment under the tiles. This 1/4" thick ply (or other) is usually stapled to the subfloor. Remove the underlayment with the tiles still attached, then prep the subfloor.

Install the cement backer with thinset mortar and fasteners per manufacturer's directions. Don't forget to tape the seams with the special fiberglass mesh tape.

If the floor needs leveling, it is done over the cement backer. Then set the tiles.

Jaz