My 1928 home has galvanized pipe throughout. I have gutted a half bath on the second floor to repair some old water damage (leaking window, leaking cast-iron toilet flange). While I have the walls and floor ripped out, I would like to replace the galvanized pipe with copper.

The pipes currently run from the 2nd floor, through an outside wall, to the crawlspace below the first floor. The crawlspace is about 4' tall. The space where the current pipes run is in a box, aproximately 7" x 7".

My question, is what is the best way to get a new line run from the crawlspace to the 2nd floor?

I'm assuming I won't be able to flex a 10' piece of rigid copper pipe enough, within the constrains of the 4' crawlspace, to be able to slide it up the wall cavity (or will I?). And it seems soft copper is not code for above ground?

The walls in the house are plaster over wood lathe, so chopping into them is certainly a last resort.

Also .. what about supporting the pipe through such a run? Would it be okay to have it supported only at the top and bottom of the ~10' run? (I'm asking this, assuming I'll use rigid copper, as I have another bathroom which I would like to replace the galvanize pipe to as well -- but I have 7' of basement clearance below it.)

Thanks in advance for the help.