Is the tub filler installed in the tub? This wouldn't be legal today, I don't think; they are required to be above the flood plain of the vessle now. Anyways, once you remove it, remove the tub, why can't you just reinstall it hanging there? Whether it is copper or galvanized, you can buy caps, either screw them on, or solder them in place until ready to reinstall things. Post a picture, and maybe other suggestions will be evident. You'd proably want to cap the drain, but that isn't as important if the trap is left in place.