We will definitely have smaller announcements than Fire Emblem (Yoshi is definitely one of them), I mean you will always have some games/announcements that are bigger/smaller than some others.

Before or a few days after the investors meeting.

List of Nintendo Direct presentations in previous years in April, May and June (before E3):

2017:
April 12 - Arms, Splatoon 2, Nintendo Switch and Nintendo 3DS games
May 17 - Arms
June 6 - Pokkén Tournament DX, Pokémon Ultra Sun and Ultra Moon, Pokémon Gold and Silver

2016
May 11 - Culdcept Revolt (Japan only)

2015
April 1 - Wii U and Nintendo 3DS games
April 24 - Xenoblade Chronicles X
May 7 - Splatoon
May 31 - Wii U and Nintendo 3DS games
June 1 - Nintendo 3DS games
June 14 - Super Smash Bros. for Nintendo 3DS and Wii U DLC

2014
April 8 - Super Smash Bros. for Nintendo 3DS and Wii U
April 10 - Tomodachi Life
April 30 - Mario Kart 8

2013
April 1 - Nintendo 3DS Download Software (Japan only)
April 3 - Tomodachi Collection: New Life (Japan only)
April 17 - Year of Luigi and Nintendo 3DS games
May 17 - Wii U and Nintendo 3DS games
May 27 - Monster Hunter 4, Phoenix Wright: Ace Attorney − Dual Destinies (Japan only)

2012
April 21 - Nintendo 3DS and Wii games


So there is realy high chance that we will see some kind of Nintendo Direct (maybe Smash Bros Direct?) in April, May or early June. Only in 2016 we was't have any Direct for Europe and North America at this time (but WiiU was almost dead by then).

Well duh I never stated otherwise.

My point of that post is if Nintendo is wanting to push Fire Emblem to its maximum potential (Which I'm assuming they do want to) Smash being the main focus of E3 (assuming it will be) and then if they include something like Animal Crossing, footage of Metroid and or Bayo 3, the coverage will be minimal on FE. However, if they reveal it before that, there will be huge media focus surrounding it, especially if it's graphically pushed to the max, which they have done with each iteration. (PoR, Radiant Dawn, Awakening, Fates and Echoes all looked amazing for the platforms they were on)

Fire Emblem is going to be a bigger game and will also need more marketing than Yoshi. Yoshi will sell regardless of when it's announced lol. 

So yes, of course there will be smaller games and bigger games than others. But Fire Emblem should really be pushed extremely hard with this iteration, considering the success of the 3DS games and the mobile game. And it would be hard to do that with Smash being the center of E3. (Even more so if they show AC, Bayo 3, MP4)

The bolded are also assumptions. Assumptions can be made for the other side aswell, for instance E3 will likely draw a lot more eyes than a Fire Emblem Direct would. Nintendo's Spotlight will be watched by fans of Smash, Pokemon, Fire Emblem, Animal Crossing, Metroid, and so ons alike while a FE direct will only be watched by FE fans primarily. These too are assumptions, but ones I don't think many would disagree with.

Regardless of all that, I think a Fire Emblem direct is highly unlikely as game specific directs are usually for already revealed games that are releasing soon. Mario Tennis Aces and perhaps Octopath Traveler should be in front of the line for a game specific direct.

Like I wrote, there are always some games/announcements that are bigger/smaller than some others and that Nintendo always want that evre game they have to be sell much better, of course that doesn't mean that evre smaller game than Smash will have own Direct. :D

I just dont see why Fire Emblem would need to be pushed so hard that would needs own Direct compared to other games from E3, especially because Fire Emblem is totally different game compared to evre other game Nintendo could show at E3. I dont say they Fire Emblem will not have own pre-E3 Direct before E3 like Pokemon had it last year, but IMO higher chances are again for Pokemon or AC pre-E3 Direct than for Fire Emblem.

Pokemon Boom end of April!

I think there'll be one before E3. Sometime in the next 3 weeks.