If I understand your question correctly, you are asking us for suggestions on how to create a "jester" type droid for a Star Wars RPG. There's probably several Star Wars RPG systems by now, and I wouldn't know the statistics of all the droids. But it would make most sense to me to simply model him on an existing droid that can talk. That is, presuming he is a talking jester, and not just a bumbling buffoon. For a talking jester (one that can tell jokes) you can use your standard protocol droid as a template (C3PO for example). But if he is a none-speaking jester, you could also use a Pit Droid. Pit Droids are already bumbling idiots, so they would make for perfect jesters.
