I can see it being red too. So... going for a Red Emblem, the rest of the banner would be:
Embla, Elincia, New Emblem
Byleth, Mycen, Isadora
Seidr, Camilla, Nino
Arval, Ginnungagap, Tina/Safy
This sounds possible. Then save Severa for April, since she is the only red hero in the waiting list. Doesn't help that these past 2 New Heroes banners had both a red demote. They need to add another 5* Red hero this Friday.
April, imo, may be Blue.