Just an update: how's nightmare sound? Removed +/- 1 1/2 tons of old flooring, only to find that the joists were out of level, in both directions, by 1 1/2"!! Removed and replaced every joist instead of sistering as planned.
Now that we finally have the subfloor in, I have a 'Chicken or the Egg' question. I want to get the tub in place and then tile the floor. New walls to follow. My reasoning is to allow a bit of a gap that can be siliconed "just in case". The other half wants the walls in first, "because".
Does it matter which goes in first?