I want to move a toilet in an existing bathroom, but it is on a slab that has rebar. Can this be done without jeopardizing the integrity of the foundation?

You can cut the concrete slab and rebar and not jeopardize foundation as long as you don't distrub or undermine the footer under the foundation.

I asked our Plumbing Expert to take a look at this, too.

Skiberber, would he just take a partner saw and cut a path from the current location of the drain to the new place for it?

He can cut the slab or use a jackhammer.
What kind of slab is this? Is it a slab-on grade or is this a floating slab in a basement?