Regen will regenerate HP eight times, then the character will be able to move and choose other commands. I verified this on at least two characters besides FuSoYa. (Sidenote: Does anyone know if this command always restores 10 HP per character? That's what I'm finding, at least in FF2us.)
8 times huh? Hmmm. The only difference between the SNES version and GBA version is that the GBA version doesn't force you into uselessness while using Spirit and allows FuSoYa to use his turn doing something more useful after the initial Spirit cast.
Recall can be used on anyone (I've tried it on at least four different characters), and casts a random black magic spell. If the character doesn't have enough MP for the spell (like Edward) then the battle sprite walks forward and performs its "special" graphic. For Edward, this is when he hides, which looks like sweat (or tears?) coming out from him.
Recall targets all enemies, regardless if the original spell is able to target all enemies.