New Redemption Grab Bag now includes an assortment of 500 cards from five (5) different expansion sets. Available at Cactus website.
Cherubim + Ethiopian Treasurer + Spiritual Warfare will ignore all human ECs pre-block. Of course, ET isn't really Royalty.
I have been playing purple kings forever. (and for credibility) I just took 2nd in T1 states and 1st in T2 using my kings.I have found extreamly little synergy with kings and angels. I think you'll fine they would just be 2 offenses in one deck. Personally I pair them with a small bit of Prophets, but I don't know how that will effect your concept.Ps: play with Abby... She is Amazing and underrated!
The Kings don't have good FBTN so you can always make a little captin combo.Playing unified kingdom on David makes it CBN so you can use it on him, band to everyone and their grandma and then through in a FBTN OT angle.