I’m not sure if I’m posting in the correct place or not…

We are in a 1920s two-story house in NJ.  Last night we ripped out part of our kitchen ceiling to view the flooring of the bathroom up above it and to create space for reinforcing the floor joists (kitchen ceiling had to come out anyway–there had been some unsightly water damage in the past).

We know that the original yellow pine hardwood is there and have refinished this in other areas of the house.  We can see that some areas of the original wood floor around the tub drain and vanity (can’t see toilet yet) have been ripped out to accommodate pipes.  In the bathroom we can see that on top of the hardwood is a 1/2″ layer of plywood subfloor, a 1/8″ layer of some vinyl/tar-like sheet of something, and a 3/16″ layer of small tile.  Our issues are as follows:

* Do we try to preserve the original hardwood floor and patch in around the torn up areas?  How hard is this to do and what are the pros and cons of hardwood in a bathroom?

* If not, do we put new subfloor and tile on top of the old hardwood or rip the hardwood out and work directly from the joists?  I think that if we add new subfloor, leveling sand, hardibacker board, mortar, and ceramic tile that we will have gone beyond what the current toilet flange height will allow.

* We are going to be replacing the tub with a cast-iron clawfoot tub (4 1/2″ foot petite style).  How do we make sure that our floor can accommodate this tub.  I think the tub currently there is an older cast-iron variety.

* Should we look into replacing all the old pipe since it is exposed via the kitchen or is this better left alone?

Thanks for your time!  It is our only bathroom in the house and we are trying to anticipate and take care of as much as we can before we actually rip out appliances to minimize the time we’ll do without.