Over the pass few days, I've been banging my head against the wall trying to figure out what the heck is wrong with this, but I think my research and testing might have paid off.
With the car off, I can go through all the gears with no issues. While the car is running, I can barely get into any gears (reverse is impossible unless rolling backwards or started in reverse) with the clutch depressed. With the clutch pushed to the floor, on a even surface, I can go to put it in gear and where I feel the resistance starts, the car will ever so slightly start rolling forward. Lifting my foot up from the floor in first, and I can feel the clutch engaging almost nothing from the floor.
I had to take out my winter mats just so that the clutch can go down as far as possible, else I can't get into any gear.
The car is driveable only with double-clutching, else there's too much resistance to change the gear without the revs being close.
From what I've read, these are symptoms of a failing/failed slave cylinder. I park in a garage every day, and there are no leaks, and my brakes work normally. Fluid level under the hood is normal.
Am I on the right path here? If so, is there anyway to confirm that it's the slave?