In removing a tub. They tell me there is a tub drain removal tool.
Some fit on a socket other use a wrench to turn out the drain.
The other part is the drain adjustment rod . That is held in place by two screws.
I guess that is the whole assembly? See pictures

Doesn't look like that tub will be reused? Niether will the waster and overlfow assembly. I wouldn't waste money on a tool for removol at this point. I would just take a sawzall with metal blade and cut the drain ring in four spots and pry it out with a flat blade screwdriver, or chisel. Then simply remove the two screws from the overflow plate and pull the rod up and out. You are now ready to tear the tub out.

If you have access to the tub drain from behind, or below the tub, you could simply disconect the assmebly from the trap, and not even bother with removing the parts from the tub.