Perhaps when you become a spawn, just before you wake up the game forces you into a limited character creation screen where you can choose the type of fangs and the new skin and eye colour? Everyone should be happy then.
As a side note, I always wondered why Astarion has unique eyes and fangs in comparison to his brethren. Even Cazador has a reddish glow in his eyes.
Also, if Astarion is ascended he should probably get his reflection back, after all he's supposed to benefit from human perks.
The eye thing might be from tadpole, I kind of headcanon that he had similar glowing eyes like his brethren before getting tadpoled, I mean it already makes it so that the normal vampire rules don't apply to him, like running water, sunlight, OCD need to count stuff, religious symbols, needing an invition aka normal vampire stuff.
Most people don't know about the Vampire OCD thing, like if you're trapped in a corner with a vampire, you just need to throw some rice grains or coins, they would stop whatever they were doing, even hunting you and start counting the stuff you threw individually like one by one, it even overrides their self preservation instincts, since if you threw a lot, they'll still be counting after sun is done rising, you could potentially trap a vampire on a beach just by throwing sand at them.
