I can tell I found it easier to chip the thinset off the tiles than I expected.

As for the floor...?
Why don't you ask your tile guy? You don't need to be making a bad thing worse.

I'd cover everything with plastic then. including open doorways to other rooms. every little bit you can keep OFF of your other stuff the better. and less to clean later.

I've still got some areas with vinyl still attached... gotta work on that. yuck. It shouldn't be as messy as yours will be tho. I still dread it.

Our entry tile was taken up while we reno'd then whole house so at least I didn't have to worry about dust at that point as the whole house was a dusty, gross, gutted, to-the-studs mess. DH chipped the thin set off with a large, wide scraper he rented. I remember he had trouble finding the right tool and procrastinated the job as long as possible.

Wait....we don't have a slab though so maybe your situation will be worse than our car decking sub floor?

DH attempted getting the thin set up with the chipper hammer and it didn't work. it was easier for us just to take the sub floor up, replace the base and then start with a clean slate. Good luck!

First thing I would try is a "demolition hammer" or a "rotary hammer" (set not to rotate).

I doubt your DHs idea of getting the leveling done in the same step will work, although his grinding idea may work.

I went to a flooring store today to pick out new tile and am having someone come over to give an estimate on leveling the floor as well as measuring for tile.

The salesman said that most of the time they don't worry too much about the thinset that is left on the floor because they just cover it with more thinset. I don't know about that, but I'll see what the estimate is.