The decking can be demoed and replaced, but I would suggest:
-Leave the pool full of water during the work, to keep the walls from collapsing into the pool
-Do the demo work by hand, not with a skidsteer or excavator. The walls are tied into the deck by rebar that runs up the back of the walls and is then tied to the rebar in the deck.
-Put the plumbing under pressure before the demo work starts, and until the deck is fully poured.
-The right contractor can remove those white coping strips and pour the new deck with a cantilever form.
-The rebar coming up from the back of the walls MUST be retained and tied back into the new deck. It is the only thing keeping the top of the walls from
It looks like the tile is set in a track, should be straightforward to remove it and reset some new tile.
The rust looks to be from a seam in the panels. Depending on how far you want to go with this thing, you could have the paint blasted off (I would use hydroblasting or some alternative to sand blasting to minimize mess and likelihood of making holes in the walls). After that, the walls should probably be primed with some kind of rust inhibiting primer, then repainted and the seams re-caulked.
The floor can probably be prepped and replastered - nothing special needed.
On the deck, I have also seen people use L-shaped renovation pavers to cover up the deck and the white strip. Might be worth looking into.