[Bryce_Hego]

It's really not complicated for Zerans, is the weird thing.

If it were, we wouldn't have Glykin, Hyattr, or Phenex - races right up the same alley as Zerans, especially in the first two's cases since their names are also deviations of their god's names. They were heavily related to gods (Glycon, Hyatt, Helondis) - especially since Glycon created Glykin much like Zera created Zerans - and yet we still have them in Korvara with no bans or anything. And not to mention Papilions, while not being god related but being 100% related to Kysei, are allowed in Korvara despite that as well.
Zerans being banned still feels very arbitrary since very similar races were allowed to 'hand-wave' their lore connections to gods.

If anything, they couldn't've shipwrecked in Korvara centuries ago, lost their lineage story, and now just exist and are considered one of the odd freaks of nature that every weird race is?

My thoughts exactly.
If Hyattr can be called Hyattr without Hyatt, that more or less sells that Zerans don't have any excuse to not be around just cause it's similar to Zera. (Though I think it's weird when people refer to Magmic ore as Nerif Blood IC)

Unrelated but still strange is that all G6 humans are playable in Korvara with no lore complications, but the Korvara humans can't be played in G6?

I mean, I suppose for Zerans specifically their racial traits are direct references to Zera and Zera's teachings, which just don't exist in Korvara.

I don't believe this makes any sense, or the description of many items and materials would have had to have been changed for Korvara. The flavortext of perks shouldn't be an issue of any kind, as it's merely that, flavortext. If a new player mistakes it as accurate Korvara lore you'd have to correct them, just like any other situation of something similar.