I have the following problems throughout my 1970s block and rendered internal solid walls:

1. Plaster separates from the render all too easily leaving a very soft cement render surface.
2. Tiles in all rooms are blowing off the render in sheets of tiles+plaster.
3. Steam wallpaper stripping merely causes the plaster to blow off the render.
4. Much of the emulsion paint on the walls flakes away from the plaster leaving large patches of bare plaster.

I would like best advice on how to:
1. Stabilise the revealed render surface ready for new for tiles.  I have applied 2 coats of PVA to seal the surface but will this give adequate adhesion/strength for tiling direct onto the render.  Should I apply a skim plaster coat first.
2. How can I remove wallpaper without steaming or bringing off large patches of paint.  I have heard of a chemical peel- any advice?
3. What is the best way of repainting the walls to result in an even painted finish?

Overal, what has caused this problem.  Was the render not mixed properly, or not left to dry before plastering? Did the blocks suck all the moisture from the render? Were the walls painted before the plaster was dry?