Another bathroom remodel, with questions

A previous house, had a huge remodel around 1773, there are no records extant for anything before that. When I bought it in 1996, it had evidence of just about every type of utility innovation possible. Its own gas generator in the coach house.
A hand pump for moving water up tot he two huge tanks in the tower - obviously that's servants hands.
Wiring was from cotton covered single strand, for lighting only to the latest in early 1950's, rubber insulated, where the rats hadn't gnawed it - several had tried too hard and immolated themselves - we discovered the mummified skeletons. The previous owner had just retreated into less rooms.

After trying to save as much as possible that was at least safe and functional, we more or less gave up. For the plumbing we used the multilayer tubing for everything, because they were easily adaptable to join to regular copper, as at boilers etc.
A mega advantage for us was the fact we could cable in long runs of pipe. The building had been heavily added to in the Victorian era. At that time it was owned by a famous racehorse trainer, and with every win, he added a room or a wing, or tower... The floor levels rarely coincided as building fashion lurched through the Gothic period, so that was a big point in favour of a flexible solution.

Nice as the huge copper and bronze waste pipes were, they got replaced too, except the short visible sections, which we had nickel plated. Plastic is not only very easy to work but cheap as chips.