Ooh. New voices in the mix!
Mustafa
EN: TJ Storm (Strider Hiryu from Marvel vs. Capcom)
JP: Kenji Hamada (Azama)
Mirabilis
EN: Heather Halley (Cassandra Alexandra from Soul Calibur, Para-Medic from Metal Gear Solid)
JP: Misaki Kuno (Hawk from The Seven Deadly Sins, Poppi from Xenoblade Chronicles 2)
As for Say'ri, considering that Cup of Tea Productions, the English voice recording studio for Fire Emblem, has temporarily suspended voice recordings due to Covid, this is probably why they weren't able to get her voice lines recorded. Until then, I would probably expect more situations like this.