Hmmm... Writey McWriteface does have a certain appeal though...
In all seriousness however, NaNoWriMo has name recognition, and I don't think making it fediverse specific will foster mainstream appeal (not that that needs to be the goal ofc). I like the International angle, call it InNoWriMo and have a slogan about being Innovative!, or unleashing your Inner writer!, or Innie belly buttons or something.