I have absolutely NO interest in breathing in the off-gassing from nichrome, nor from some undefined "titanium"...
Surgical stainless steel, or certified grade 2 Ti only. Sorry. Next?
I get the attitude and all, but fear you're in for disappointment. Stainless steels are basically Nichrome diluted down with Iron. Look it up if you want, but SS has a lot of Chrome (like 10%) and some Nickle (say 5%?) at a minimum. The most common 'series 300' stainless steels are about twice that (18/8 being a biggie).
Nichrome is typically 80% or so Nickle, the remainder Chrome. So if the goal is to avoid either hot Nickle or hot Chrome at all costs, SS is probably not an option.
OF
Edit:
As long as we're on the subject of materials, perhaps a brief rant on ceramics might contribute?
Ceramics, as materials, cover a LOT of ground. For our purposes we can limit it to metal oxides, Aluminum, Silicon and Oxygen for the most part. In practice, small particles ('grains' if you will?) are forced together and sintered together. That is they are heated to less than the melting point, but high enough so bonds are formed linking the bits together. Glazing is simply more of the same sort of stuff, with no crystal structure (amorphous) with a lower melting point, sort of like a coat of paint.
Pores in unglazed ceramics are controlled by the materials going in and can be increase on purpose by several techniques at the expense of strength. Obviously, glazing seals the surface, making it essentially glass.
Kaolin is a traditional clay for ceramic use. Naturally found in river banks and such in varying grades ('other stuff') but basically Aluminum and Silicon oxide. The key property giving element being the Aluminum part, leading to the ultimate (synthetic) in the class, Alumina (Al2O3). Same basic thing as Ruby and Sapphire, FWIW.
IMO Kaolin is an excellent ceramic choice (some might argue Alumina is superior, not to mention Zirconia based ones.....), and since it was 'fired' at a much higher temperature than we will ever use I think it's pretty safe those terms (no outgassing). Same as lead can show up in glass (by intent.....), it can show up in glazes (either by intent or accident). Clear glazes, like we'd be using most likely, are highly unlikely to do so since most of the lead is coloring.
While it should be checked of course, I think, in general Kaolin and glazing are safe ways to go.
Fun project, IMO shows great promise, be fun to watch. Best wishes to those involved.