I suggest to remove the clutch slave actuating rod pin and see if you can push the slave cylinder back by hand to establish whether it is truly a slave problem or more likely a clutch problem.
I hate to say but I have a feeling you may have over extended the clutch fork and it has popped out of the retainer on the throwout bearing and not seated back correctly. This may explain both the non return fully and hard clutch pedal. I'm not sure whether you'd be able to see with a flashlight in the sight hole of the bell housing.
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