That definitely sounds like something doable. If the pair approaches the receptionist desk and asks for any new reports that came in, they will be handed a mission to the Kiev to take out some imps before the problem gets worse.

It looks like they're clear to take a mission at any time, so they may depart whenever you two would like to send 'em out.

Their mission will in turn end in success, and they obtain two kishin egg souls. Just make sure you post the log proof up on the Soul Tally so they can be marked!