Rather tame a hobgoblin. They're just adorable with their big horns, twin tails, and the little grunts/squeaks they make. I imagine an individualized vex unit would be much like Odo from Star Trek DS9. Just gotta find a way to disconnect them from the vex wifi.
Perhaps try asking Calus? Apparently he managed to indoctrinate a vex mind and it's subtype followed