When I first saw the trailer, I didn't notice anything distinctly SMT or FE about it. At best, I recognized Tiki, but I didn't care enough to rewind the video at the time and just assumed otherwise.
Fun fact is that Persona is technically not supposed to be branded as a spin-off of Shin Megami Tensei, but the original Megami Tensei, and in Japan was known as "Megami Ibunroku Persona", only sharing the "Megami Ibunroku" brand with Devil Survivor. In Japan, this game is titled Gen'ei
Ibunroku♯FE, which pretty much cements the fact that this crossover is now Persona/Devil Survivor and not SMT, despite initially being teased as such way back in 2013.
I actually originally wondered why they chose SMT instead of Persona to crossover with Fire Emblem. The target audience of SMT is mature, whereas Persona and Fire Emblem are more the teenage anime crowd. Can't really say I'm surprised they made the switch, but I am surprised by how loosely related it seems to be.
Relevant pics I found on GAF:
All it needs now is Featuring Donte from the DMC: Devil May Cry
TM Series.