Defeat the Bosses from each base. You can then defeat them again and have the chance to recruit them at the indicated guild.

Hannah: Go to Balterossa then to the Union Of The Golden Chalice to recruit her.
Hinnah: Go to Nagapur then to the Union Of The Golden Chalice to recruit her.
Ludope: Go to Melphina then to the Union Of The Golden Chalice to recruit him.
Milton: Go to Royotia then to the Union Of The Golden Chalice to recruit him.
Snievan: Go to Elysion then to the Ring Of The Labyrinth to recruit him.
Young: Go to Baaluk then to the Union Of The Golden Chalice to recruit him.
Zuido: Go to Ghor then to the Ring Of The Labyrinth to recruit him.