Yes, the electronics would probably be a mix of COB for the stuff they buy that is mass produced, like the digital voice package, where you can fit it pretty much into a SRBP chip carrier like used in greeting cards, and then a few motor drivers for the mechanical partws, and a microcontroller for the smarts. You could probably use smart lamp controllers for a lot, as it is not exactly high processing power for the most part, just complex mechanically for the "interface" parts, which has to be flexible and heated. The rest is just bulk silicone in most cases poured onto an armature after adding all the electronics and such, and in a polished and waxed mould so the silicone releases properly after curing. Then cleaned and painted.
Yes I have seen and touched them, not the full animatronic ones but the cheaper silent " fully correct" exaggerated Japanese ones, as a shop I know imported 2 of them. Dave might have heard of the ex owner of the chain, he now is living well in Australia, and I have met JT a few times as well.