Regarding what was established, we never really learned that the grey individual from "Conspiracy" would have been a Bolian.
Actually, even though he may have appeared more grey onscreen, Captain Rixx was very definitely blue. Then-staffer Tracy Tormé once revealed at a New Zealand convention that his original proposal for "Conspiracy" included an Andorian
, and it would have been their first TNG appearance. Rick Berman told Tormé: "We don't do antennae on this show."
So the makeup artists went ahead and did a blue alien anyway, simply leaving off the "hokey" antennae. And the Bolians were born.
In fact, if I recall correctly, Dexter Remmick
was originally suggested as Andorian in his first appearance, but that idea was quashed early. Remmick returned in this one, and they finally got a blue alien, Rixx, past Berman.
I may be wrong, but I thought I read somewhere that Rixx's makeup was actually blue, but the lighting they used on the set made it appear that off-greyish indeterminate color.
Ha. Didn't see your post. Yes, it was due to the weird lighting on the planetoid, IIRC.
And the lighting on Lal's Andorian persona, in "The Offspring" (and Shran's daughter, Talla in ENT), gave them a greenish hue.
The "Enterprise" Andorians have an orange base coat of makeup, when allowed a more pure blue topcoat to show as reliably blue. Talla probably had no orange base because she was half Aenar.