I recognize that Java natively supports 64x skins and one requires mods to use 128x skins, but some do exist. I know at least HD Skins allows 128x skins to be used, and doesn't break Ears rendering when using 64x skins (at least it didn't when I used the template skin). I am unclear if Ears already has 128x skin support or not, so apologies if it does and I've made this issue erroneously. If it doesn't, I'd LOVE to pair Ears' features with a high fidelity skin though. Thanks for reading and all you've done with the mod so far! :)

Getting HD Skins working would (I think) take a notable overhaul.
Despite skins seemingly working, the codebase assumes a 64x skin all over the place. It would presently lead to a bunch of weird and unexpected problems.

The reason Ears assumes a 64x skin is because we piggyback off the Mojang skin servers, which will only ever give you a 64x or 32x skin. For 32x skins we upgrade those to 64x manually.

Personally, I think it'd be worthwhile to overhaul this for at least naive support.
We can't integrate with third party servers (such as HD Skins) as tightly as Mojang's simply because there are a lot more of them, each making their own assumptions about how to process the skin file and what to send us (the client).
I don't think supporting this would require tight integration, however. We'll see.