Great job!
Ultimately, feel free to take some ownership of the visual aesthetic (you're active, I'm... having underattended office hours this semester?) so please, please take anything I say as advice rather than a demand.
My comments -
I'd envisioned the eyes themselves a little larger and the turret area slightly convex rather than concave, with the skull in general extending a little further to each side than it appears to do here (the latter in order to provide sufficient allowances for the pocket where the rear hinge of the jawbone moves to have substance to the side of it on the head -- doing some sketches where the upper jaw is in the open position will probably help to figure out what the relevant implications are) When going to 3D, be sure to examine whether you have the eyes in the sockets so deeply that they can't look up, or the turrets so extended that they've moved from chameleon-style eyes to shrimp style eyes, as both have some implications (in the latter case, acceleration-flimsyness) Similarly, top down pictures can help show (intended/actual) sight lines, blockages, and the size of the stereoscopic region.
It might be nice to show/design some of the skin folds/sags around the rear of the top bony jaw plate where it moves relative to the fixed portions of the head.
I envisioned more protruding lip around the breathing cleft (visual indications of the capacity to close said cleft by tensing/relaxing lips?)
I tended to mentally picture the rumblers wandering somewhere closer to "second chin"/wattle territory, but they're fine where/as they are
Cross-thread answering a bit from the 3D thread this spawned:
I believe it's stated somewhere that the eyes are milky-green? This can be changed if it gives you a better color palette.
Remembering that it's a bit dim where the Aera developed, but the Aera are still visual creatures, the maximum pupil size is probably fairly large.
Personally, I'd avoid over-weaponizing the tail too much, or otherwise making it too big a feature. It's there for balance. If you're looking for inspiration for pre-technological Aeran tooth-and-claw level engagements, my internal model was usually something along the lines of "semi-arboreal, pack-hunting jungle ferrets" (if that makes any sense to you).
For the cockpits -- great seeing that, by the way -- also recall that the level of fine motor control goes front limb digits >> hind limb digits > mid limb digits
For body articulation, (I wish I could remember where the relevant posts were) I believe there's a discussion somewhere about Aerans not being mono-vertebrates (4 primary vertebral structures with interleaved floating ribs in a bilaterally symmetric configuration and interesting hip-joint connections). If no one can find it, then, it may well vanish, as no one will probably really notice either way.