There is an interesting pattern with the order of reveals (the Smash X “IP”) of each Mii Costumes Waves:
Min Min
- Ninjara (ARMS) -> same IP as fighter
- Heihachi (Tekken) -> returning Smash 4
- Callie and Marie (Splatoon) -> former assist trophy
- Vault Boy (Fallout) -> “popular” request
Steve
- Creeper, Pig and Diamond (Minecraft) -> same IP as fighter
- Gil (Tower of Drouga) -> returning Smash 4
- Bomberman (Bomberman) -> former assist trophy
- Travis (No More Heroes) -> “popular” request
I think this pattern is likely to happen in the next challenger packs. With Sephiroth, I think we will get 4 Mii Costumes, as with both Fighter Pass we have been getting an average of 5 mii costumes per wave, last time we got 6, so I think that we will get 4.
In addition, as you can see, we are getting 4 “Smash X IP” splash screens on last two FPs. Also, there is the same order: 1) Same IP as fighter, 2) Returning Smash 4, 3) Base game Assist Trophy, 4) “Popular” request
The first Cross Splash screen we will get is “X Final Fantasy VII”, so I think it will be a Tifa mii costume, as she is very popular among FF fans.
The second splash screen can be Chocobo hat with “X Final Fantasy”. The third splash screen is where my theory falls as I don’t think we will see an assist trophy mii costume, instead we will see Geno mii costume (with a Smash X Super Mario RPG).
The fourth will be a “Smash X Chrono Trigger” with a Chrono mii costume. He is a popular request, so fits the last criteria. Moreover, Chrono Trigger, Super Mario RPG and Final Fantasy VII are three square RPGs that were released very near, between 1995 to 1997, so this Mii costume wave is to appeal people who liked mid/late 90’s JRPGs.
EDIT: And in case the rule “a square character only comes with square content” can be broken, I can see the assist trophy promotion being Aluccard (Smash X Castlevania SOTN splash screen) as his game, SOTN, was released in 1997, same year as FFVII (in the same console, the PS1...) and they have some physical similarities, like the long white/silver hair.
In addition, the “popular” request splash screen will be Geno but with a new mii costume, so it doesn’t count as a smash 4 returning
In summary, here are the two possibilities:
One
1) Tifa (Final Fantasy VII)
2) Chocobo (Final Fantasy)
3) Geno (Super Mario RPG)
4) Chrono (Chrono Trigger)
Two
1) Tifa (Final Fantasy VII)
2) Chocobo (Final Fantasy)
3) Aluccard (Castlevania SOTN)
4) Geno (Super Mario RPG)