I do have a couple of thoughts as to perhaps why #Hemmer's antennae don't move in #StarTrekSNW. (Noticed this was mentioned in a couple of tagged posts.)
1) From a practical standpoint, I believe they use servos to move the stalks. Servos are REALLY loud...
It's pretty cool use of remote puppetry, but when it's right on your head your hearing can be limited quite a bit. For an actor who has limited vision I'd imagine that would be even more difficult as verbal cues might be lost along with complete visual cues and direction.
If you notice, Ryn's prosthetics in #StarTrekDiscovery even had a latex cap encompassing his ears to give the impression that he had none. Hemmer's don't have that. That further leads me to believe it's for the actor's benefit and safety to safeguard his hearing.
2) I can think of some reasons on possible cannon reasons as well. Hemmer might have found that his antennae moving was a distraction to humans not familiar with it. So he might be making a conscious effort not to move his antennae for the sake of working with others.
The Federation, in general, isn't completely tolerant and being the only Aenar in Starfleet Hemmer probably had to make a lot of changes to his behavior to succeed in making it as far as he has. It's sad, but true, as Una I'm sure could attest.
As far as a cannon reason for having ears, could just be an Aenar thing in this iteration! This is the first Aenar we've seen outside Enterprise so anything goes on that species' physical appearance. At any rate, no one needed to read this more than I needed to write it! YW!
