J'accuse!
So after getting the car up on ramps and jack stands, filling the reservoir, pumping the pedal, and watching underneath... the slave cylinder was dry and so was the hydraulic line going to it, even after wiping them down, but still drips coming from the transmission.
To remove the slave cylinder I used an 11mm flare nut wrench to remove the hydraulic line. Then the two nuts holding the slave cylinder on were 13mm. Top one was hard to get to, ended up using a short 13mm socket on a wobble extension, then a knuckle, then a regular extension to get it off. Easy peasy with the right tools... some of which I had to leave the parking lot where my car was stranded to get...
Anyways, looking at the two parts, its pretty easy to notice that the pushrod is missing from the old part. So I'm guessing thats stuck in the bell housing somewhere? I assume I'm going to have to drop the transmission to get this out, right?
And I think its safe to assume I shouldn't just put the new slave cylinder on and plug along forward. Seems like having a metal rod floating around in there would be bad.