Few questions on tiling ply and walls

[Daz]

On the ply floor with most flex cement based adhesives there is no need to prime the surface before tiling. However, the bottom of the boards and the edges should have been sealed with eg. SBR before fixing.
Consider fixing a decoupling membrane eg. Ditra to the ply before tiling but if all is rigid and stable this should not be a necessity unless using more fragile eg stone tiles.

If I have to tile a ply floor (generally under protest) I would always prime first with Ardex P51 neat as you do not want any moisture from the adhesive compromising the ply layers.
Ditra matting or any other decoupling membrane will only help minimise lateral movement so if you have any deflection in the floor you will need to sort that first.

 

[White Room]

Check the adhesive instructions some say prime some do not....