To be honest I think adding pattening to Jar-Jar is so complicated you might as well start from scratch.

Recolouring him is time consuming but possible if someone has the time and patience to do it but to add more pattern in a convincing way would require having the code for the actual digital model and altering it (unless he is chameleon like and the patterns would move across the surface of his body but even then it's a massive animating task).

Removing or altering his teeth is also time consuming but doable because he only opens his stupid mouth wide enough to see them in key scenes so going in and pulling them or the tongue may be achievable.

As for the mockups themselves, they don't seem to show what you say you are trying to do, they look like he has been hit by a bag of soot or has been singed in a fire. Keep experimenting and you may find something that takes you breath away and will wow us all in a similar fashion (try to take notes on what you do while you have fun playing around so you can replicate the process, you may accidentally create the most amazing transformation only to find you can't do it again, which would be a real pain) Tarpals comes off the best because you have applied the effect to a clearly defined area but perfoming this in motion would be almost impossible (but not entirely).

To alter skin patterns the few one step processes you can use are selectively adjusting sharpness or replacing or adjusting key colours once again this is time consuming (you can't do it as a batch process you'd have to apply it to every shot he is in and replace the original with your altered guy) but it could be done if you had the time and patience.