Risa

I don't have a good explanation for how they can breathe, how they see without interacting with light, how they can hear clearly when matter isn't really touching them and therefore can't conduct sound, etc.

That is obviously due to a phase shift in the quantum fields, which is correlated to the mass of the interacting matter (through the Higgs field). This leaves you interacting with light stuff like air and light, but prevents you from interacting with solid stuff like walls (and potentially force fields, if that would fit the episode).

Of course, artificial gravity affects the mentioned phase shift by bending spacetime.

And now I must go, before my handwaving creates enough energy to form a black hole.