ullo yaself !

If the tile is plain old white 4x4, this is a lot easier, if not...

If the tile is something that might be diffifult to match perfectly
then the key thing is to save the tile, and you won't do that by prying
it up. Everything else can be put back together, and the grout can be
matched. It's a messy job in ways.

Seems like you could use something like a Dremel to cut thru the grout
and then all the way thru the plaster and lathe, then remove the
section. Chip the plaster from the tiles. Fix the pipe. Then attach
drywall, shimming if necessary to build it up to be as thick as the
plaster. May have to build additional mini-framing onto the studs for
the 2x2 piece of drywall, so that it can attach to something. That is,
if you take out a 2x2 section and your studs are 16" apart as they
should be, that could leave you with an 8" section of drywall just
hanging there, so you'd have to jimmy rig something underneath.

Once the drywall is up, prime it (I think), then glue on the tiles,
then re-grout.

Viola!