I haven't really done much Star Wars, no. As of writing this the only thing I've drawn was some silly crossover stuff with Homestuck.

I've never thought of AT-ATs like that before, but I see where you're coming from. The only Japanese robots at the time with a palpable influence on the culture of the U.S. at the time would have been Gigantor/Tetsujin 28, and then the Shogun Warriors. Gigantor wasn't piloted like a vehicle, and even though the Shogun Warriors comic showed the robots as piloted, I'm sure a lot of people familiar with the toyline had no idea they weren't just sentient robots or cyborgs (Like Tim Eldred notes in his childhood experience. This page also mentions the popularity and impact of Star Wars, funnily enough), so the idea of piloted anthropomorphized vehicles wasn't so much a thing in the states. There were also things like the Force Five adaptations of various Super Robot shows, and I believe there were also some movies made out of other series' footage (I think I saw some of a Combattler or Voltes one once), but those weren't as well known as far as I can tell.

And I think that's all really a moot point, because as I understand it, George Lucas' vision of Star Wars was made to specifically not resemble more modern science fiction but was instead more like the stuff he knew from his childhood. Granted, I am not a George Lucas scholar nor all that familiar with the era that would have influenced him in his youth, but the paraceratherium influence makes sense to me there. Reframing the AT-AT as a giant fantastic dragon-like beast makes it sound much more like something out of an Edgar Rice Burroughs pulp. It just happens to be a robot vehicle instead of a monster from Barsoom.

Something similar to that is my guess for the AT-ST's inspiration, too. There may have been some striking cover of a novel that had a creature with that chicken-gait. Of course, George Lucas wasn't the actual designer for these things, so it could have been some experimental artist who was thinking of novel ways to do legs for robots.

I'm just about certain that Star Wars influenced mechanical designs in anime like the ones you mention, too. I remember reading that Star Wars made a big splash in SF otaku circles in Japan... but now that I'm looking it up again no good sources are coming up (which I think is less about sources not existing, and more just like they're not getting grabbed by the search engine).

The good news is that I saw the cover for the Symphonic Suite Z-Gundam record again, featuring "Hamille Bidan".

It's all very interesting stuff, though, the way things influence each other and the way you can trace things back through history. A little while back I saw this clip of a guy, Nilo-Rodis Jamero, talking about being influenced by the original Gundam working on the original Star Wars trilogy. It seems like he was chiefly a costume designer though.

...as a reward for reading through all of that, I have finally drawn another Star Wars thing. It's another crossover, though...

I'm releasing a quick font called SKYFANG! It was inspired by the logo for a video game I have never played. It's licensed under the SIL Open Font License, which pretty much means you can use it anywhere with no fuss. You can download it here!

Skyfang has 3 styles. One where the speedlines imply movement going right, (a slightly sloppier) one going left, and one that combines the two into a sort of horizontally blurry look.

Ranald MacDonald, the first native English speaker to teach English to interpreters in Japan

I'm not actually sure if he had the chinstrap beard around the 1850s, but the photo is a little ambiguous and it makes sense to me.