Not really much of a news Im afraid. Only Gav, the sprite artist involved has constantly been making live streaming videos of his sprite art lately, at least the content he shows are real but the main issue seems they are terribly slow with working on it, I mean look at his past videos months ago! Still drawing the same characters again and again, he is not finishing this game anytime soon.
We can only hope for more leaks to come on 4chan, youtube, and internet archive, but I rather do something about it myself instead of waiting around for nothing if we want to experienced Mother 4 ourselves and not let the "Scrooge" (Pastel) keep the game all to himself. This just isn't right for us and the whole EB community, honestly. a 4th game is still a must even if its fan made and not canon to the real Earthbound lol.
Besides, they only drop us 2 boring tweet posts there with nothing new about the game play or the game's story, its not too exciting to look at.