Actually, I've sorta had a hunch he might be a similar shade to Russ Hudson, except it doesn't seem like Henson has much extroverted energy. So maybe he's SiFe I---. Here's Russ Hudson, by contrast:
Random tangent: It kind of seems like there's a thing with Si leads and puppets/ventriloquism. (OTOH I don't particularly relate to it myself, and perhaps I'm generalizing on the basis of only a few examples). In the CT book where it talked about SiFe Jeff Dunham, it mentioned something about how ventriloquism can serve as a "safe" outlet for Ne's outrageousness. Along those same lines, Si leads enjoy engaging in parodies/caricatures (due to polar Ne), but don't tend to be as adept or confident at them as Ne-leads. Maybe puppets are a comfortable outlet because they are individual characters with continuity. Instead of doing lots of spontaneous caricatures, you're engaging in a single, longer-term, more predictable caricature with a narrative.
I sort of think Bubbles from Trailer Park Boys is supposed to be an Si-lead. He's usually a conscientious counterfoil to his rowdy EST friends, but uses his puppet Conky as sort of an outlet for his dark F: