You can replace it with copper (expensive and cracks easily if water freezes in the traps), ABS (also can crack easily for same reason, but cheap), PVC (fairly cheap and doesn't crack as easily. PEX can be also used for drains, but is a lot more expensive than PVC and ABS because the fittings and the tools are expensive. It is forgiving of freezing. It is easier to thread around corners because it is flexible, but for drains it has to be supported a lot because it can sag and cause pooling of water—hard to split PEX, but it can be done. If you are careful to prevent sags, PEX may be a good answer.
I've used carbide tipped blades on a Sawzall and on a hacksaw. It'll cut through most anything metal if you can fit into the space. It can be hard to find them for a Sawzall sometimes. The photo above (#4) looks like a carbide blade, but I don't know what a "ceramic" blade is—made of ceramic or to cut ceramic? I understand your frustration when you can't get the blade into the space.
formerly posted as CrawfordGene