Agree with all of your points. The lack of fangs and Tav/DUrge still seeing their mirror image were the most disappointing for me. I'd be totally fine with fangs/red eyes being optional through the mirror, but right now the fangs are not an option at all.
I found romance specific companion banter on youtube where Shadowheart (I think?) comments on Tav's/DUrge's pale complexion and strange look with played confusion and Astarion just snaps that Tav's a vampire. Not sure if this is even in the game though since in all of my playthroughs it never fired off.
Then there is a comment Durge can make to one of the reflections from the past at the murder tribunal about not needing to die because their beloved has the key to immortality.
Overall it's not much though and this just enforces the feeling that everything connected to the romances is their own little storyline detached from the main story.
