Strip back to concrete or just retile?
There will be no "in situ" re-tiling those walls and floor without ripping out all the shower and other fixturing. Then remove all the old tile back to the base surfaces of the building structure.

As far as the surface mounted plumbing and electrical conduit it is really necessary to wait till you get everything stripped away to see what is behind to make a judgement call. In the worst case you may have to arrange to shim out one or two walls with wood studs leaving enough space behind a new wall surface to accommodate the plumbing and electrical.