Please report all of the bugs you're having with Prince Ali Rescue here so we can have our exterminators exterminate them :)
After creating the skin paste Leela & Osman reverted to their pre-quest dialogue.
The soft clay does not turn into the Key imprint when talking to Lady Keli, probably because there is a quest check in place in the Leela dialogue.
Attempting to restart the quest in Al Kharid at Hassan has no effect.
Jug of water isn't accepted as a substitute of the bucket of water when making skin paste.
The dialogue option with Osman when having the key imprint, bronze bar and 20 gp doesn't show when you are doing the quest and have all the items.
Edit: You have to talk to Leela before getting the key imprint. Perhaps the option to get a key imprint before talking to Leela should be removed.