The front half of the subfloor is covered in black tar adhesive from the vinyl layer that I had already removed. (Which was the FOURTH layer of floor in there...)

The upper layer of 3/4" subfloor was mostly rotted in the back ~3' under the toilet, and the lower layer of 3/4" subfloor (actually diagonal hardwood slats here) was also soft, but only between two joists. After prying up the top layer and sawzalling the lower layer, Brian screwed in some 2x4s to support the first new piece of subfloor, then put a bead of Loctite on them.

More Loctite before putting down the second layer of new subfloor, to bring this back section up to level with the rest of the bathroom floor.

Securing the new subfloor.

Using a hole saw to cut the hole for the waste pipe.

Cutting the waste pipe hole into the cement board.

Spreading the thin set mortar onto the subfloor.

First sheet of cement board in place.

Cement board ready for some tile!

Cementing tiles.

The new floor taking shape.

Now I see why Brian likes to start at the back of the bathroom: it's tough to set those last ones as you're running out of places to stand/step, and those last ones require extra work since there's the toilet plumbing to deal with. That's why he left that empty spot on the right, to have a place to step in and out.

The final tile.

All tiles laid. Now we need to kill a few hours so they can set before being grouted...

We hung the wall cabinets in the kitchen. I'm starting to think we might want to paint in here, too.

Basement view of the new subfloor and reinforcements below the bathroom. That's the old cast-iron waste pipe that Brian sawsalled just below the floor.

Grouting the new floor.

The finished floor! (Well, it still needs to dry and have the grout haze wiped off.)