Looking for any information on the old Court Jesters puppet. Can't seem to find anything.

There's some information, not much, but some in John Towsen's "Clowns". Typically they are referred to as 'baubles', and as far as I have been able to discern, they were simply carved likenesses of the jester, with no articulated moving parts. Now, unless you're looking to be very authentic, I think you could use a simple toy vent doll, a smaller one, mount the head on a headstick with a lever and string to operate the mouth. You could cover the mechanism with some loose cloth to indicate the fool's motley. Paint the head to resemble yourself and voila, a cool jester's 'bauble' that serve's as a vent figure. I've thought about doing this for Ren Fairs, but never have. It's probably been done at some point by someone, but I haven't seen it.

I've seen couple of vintage ones over the years which were made from modified "Mr. Punch" heads.

Also, the sublimely talented British figuremaker Geoffrey Felix has made at least a few articulated ones. They are truly works of art.

I actually sculpted one out myself, around 30 years ago, intending to use it I'm my act, but ultimately shelved it because I got a bit busy with other projects.
Maybe I should pull the head out of storage and revisit the idea... The one I was working on had moving mouth, eyes, and eyebrows!