One alternative would be to ditch the square corner with protective corner bead and simply do a rounded corner in plaster*.
If this matches the design aesthetic of the house, it is a perfectly acceptable solution, and I lived in 2 different rental houses (while in college) that used this on interior doorways.
It's my belief that there's a good chance that ...
I did a house a few years ago that I replace 24 doors total (including sliding doubles for closets in 5 bedrooms). So 14 doors that I had to chisel out hinge sets.
So here is what you need to think about:
Can I get doors in the correct width? Cutting a half inch out on the hinge side will be fine. Once you get more than that there are issues (tell you ...
I'm really not sure what kind of answer you expect.
This project is wholeheartedly based on your skill level.
This guy installs a slab door in about 10 minutes.
If you have all the tools available then theoretically you can do all the doors in less than one day.
Since you've indicated that you have access to the back side of the wall, my answer is to move the plumbing. It doesn't sound fun or easy, but it shouldn't be too bad. Use grinding and drilling tools to carve out the framing and drywall as needed, then shift and re-secure the plumbing.
The 1x4 down low may not even be a problem. I'd bet that the two 1/2"...