Linoleum over plywood floor?

Yes! They did that in my old kitchen. They put the plywood down to level out the flooring... I think the product they used over the plywood was called levelastic... then they put the linoleum down. It was great... lowered the sound in the room and the creaks (old house), but it did raise the floor a bit so they had to adjust the threshold going to the carpeted rooms...

5 ply underlayment or better. Be sure the subfloor is sound and fastened solid to joists. Level the subfloor as best you can with floor leveler. Fasten the new underlayment(plywood) with staples or ring shank nails. Every 3" around perimeter of each sheet. Every 6" in the field. Its a lot of fastening, but it has to be done. Fill any voids and smooth all the seams. You would be surprised how a little defect in the underlayment will show through the lino.

You could, depending on the depth you need to make up. If you took old tile up, what is the thickness.

The best material to use for under lament is Luann, 4x8 sheets; inexpensive. You might want to check the directions for the adhesive for the floor tile because it may require to prime the under lament first.

absolutely..it should hold up well.