I've just been introduced to C.H.E.R.U.B, the heaven equivalent of I.M.P. Unlike the Imps, the employees of this Heaven organization protect humanity from demonic threats. We also see that Cherub's(or at least one of them) have appearances of sheep. This makes me theorize that like demons, every angel has a unique appearance to them.
If the cherub's defend humanity, then it shows that not all angels are evil, or that some or all have redeeming qualities to them. Perhaps angels and demons have more in common then they think? But how can the cast of HB remain the characters the audience supports when they do terrible things, and the cherubs do good things? Well, I have just the answer to that. Establish that the cherubs don't have a good relationship with Heavens higher ups.
HB and HH need to show that Heaven is a divided place in terms of the lives of mortals and demons. Some angels think they should be merciful and forgiving. But the higher ups, including God Himself, think that "Everything right is up here, and everything wrong is down there!" and often use the Cherubs as pawns. This could lead to some VERY interesting future stories in both shows, and potential crossovers.