Had a thought on those old splitting joists.

A barn restorer I talked to ran into this same situation. He ran a beefy lag screw up from below into each joist to close the splits.
Sounds like you could use a few lags per joist, that is if you plan on keeping things "original." Might even be able to put some adhesive into the cracks before lagging them. Maybe use a jack to close the gap before installing the lags.

And that ceiling sounds like a job... fun stuff!

I guess deciding on going TF or "modern" in this home's restoration ultimately depends on your budget and skill set. Might be a good time to give some TF-tech a try.