Lucifer is going to be driving Helen crazy, just a heads up.

He's also going to be an angel and he's going to make a point of eavesdropping on conversations, picking up gossipy tidbits, and generally making a subtle nuisance of himself. Basically he'll be going around Loki-ing everyone, but not doing anything so bad that he needs to be dealt with. Even worse, some things he'll be doing are going to be legitimately good-hearted, too, so it's going to be hard to pin him down when he's being a punk.

Good luck with that.