Just on a hunch (since that is all I have to go on)... I think the North American release will be on April Fool's Day (April 1st). Why? Only because I think that would be hilarious.
Also, Nintendo has been so cagy about specifying whether the North American release would be 1st or 2nd quarter, and I believe (maybe?) that would be the first day of the second quarter.
There may or may not be a Nintendo Direct, maybe in March? But maybe ACNL for North America will not be mentioned.
OK, I know these wild guesses sound illogical, but then, I don't think that Nintendo's actions concerning the North American release of this game has been terribly logical in some other respects (such as whipping up demand for this game three or more years prior to its release). So, I am trying to think outside the box.