Thanks for the advice. I added two 4x4 beams under the joists for extra support, and added two sisters, although there was no way to fit a 16' span under there, so I had to split the sisters in two. My original joists are also a weird size (literally 2"x8") so I couldn't perfectly match them. They're also apparently not completely straight, as you can see by my sisters that don't line up perfectly.
I have 4 jacks under the beams, and I'm also raising up the left hand jacks a half turn every few days to try to raise that wall an inch. Should I add anything else before putting in the subfloor, like cross bracing or blocking? I'll be putting in a very heavy clawfoot tub, as well as 1.25" of subfloor, plus hardibacker, plus slate tile. Also, what is the difference between blocking and cross bracing? Thanks again!