wet lath and plaster
Water had leaked from the tub faucet and was trapped between the wall and the shower liner. I have removed the shower liner and found wet lath around the faucet and along the wall that runs about two feet down the side of the tub and about 4 inches high. I don't know what I'll find if I remove the tub. Is it possible to remove some of the lath and plaster and replace it with drywall?
Yes it is but I would leave the lathe and put the drywall right over top of the lathe. You will need too thick of drywall to match the existing plaster if you remove the lathe. Get the tickness of drywall to match the existing plaster.