As far as I know Ed has only been peripherally involved in the lore writing of 5e. I believe at one point he mentioned on twitter that he was still in regular contact with some of the design team who would unofficially consult with him about things, implying he was not officially involved, despite it being based off a lot of his work.
If so, I wouldn't expect larian, being a 3rd party, to hit him up directly for their lore writing.