No I dont think they have announced what games will be at e3 prior to the event but we can assume animal crossing, pokemon, fire Emblem, and Mario maker 2 will be present in the direct and in the treehouse events after.
I'm surprised that there wasn't an announcement for a direct today. Not because of tax day, reggie, or the 18th anniversary but because were halfway through April and Joker for smash is suppose to be released this month and potentially the 3.0 update and we have seen diddly squat of any of that.