With the previlence of 3D printing, I imagine a Cyberdog would be easier these days.. but it's also a super niche thing/not in demand. So you'll likely be looking at paying for the full custom sculpt of a head base for that.
To my knowledge there's... almost no fursuit makers who do 'mechanical' characters because of that kinda thing x.x

As for the goat, there's plenty of makers out there who'd likely do great with them. And the hat.. I can see a few ways of doing it? depending what you want the horns made from. (Soft plush or cast resin)
If soft plush, could likely do that via magnets installed in the base of the horns and the sides/top of the head so they just clamp down on the brim of the hat and help hold it in place. But obvious issue of them getting knocked/pulled free n falling off.
Resin ones attached directly to the head would obviously be more stable n sturdy, and would only really need some careful planning on hole placement in the brim? just might be a little tricky to take off while wearing him.

As for glasses.. there's alot of suits with those now, so I do not see those being a problem? Most are a simple printed 3d model or made with some shaping wire and bondo clay

Yeah I can easily rationalize why cyberdog heads haven't been seen, or brain domes for the matter due to the need to make a smaller thing visibly fit within an already space-constrained object.

As for the goat horns, I've imagined that it could be possible to avoid hat holes entirely if I can make the horns magnetically detachable