Let me point out the Question and Danuser's response to which I'm assuming is what you consider Lanesh's blue eyes to be canonical.
https://twitter.com/SteveDanuser/sta...87595542433792
Question:"I know you probably wont see this question, or know the answer (Because its still a mystery)
but do you happen to know who "exactly" Lanesh the Steelweaver is, and why he has blue eyes?
Steve Danuser's response: "I did see this, and I do know who he is. Would rather not delve into character backgrounds here, as someday there might be an opportunity to tell the tale in game. That's always more satisfying than an off-the-cuff tweet.
"
Nowhere is he confirming that blue eyes is canonical/does make sense for Lanesh. He's simply saying he knows the character.
Nothing here is saying his blue eyes are canonical. This is just like when Anti-helf folks thought Ion's statement in April 2018 meant Blue Eyes were coming to Blood Elves and that Blood Elves would get all colors of the rainbow for their eye color options.
Your own assumptions are not canonical. The girl asked
two questions in one sentence, Steve replied to the first bit
The "would not delve into character backgrounds as someday there might be an opportunity to tell the tale in game" is another way of saying "we have no plans to do anything with this guy atm, but in case we ever do I'd rather not confirm or deny anything right now."