The moons thing could be difficult to track with long travels, moonless nights or underground adventures. For the mages, I've two ideas that may work, but its been a while since I opened a DL book.
1) There's no cleric in your game. Mages use the Theurge from UA, but use different Domain for the level 2 feature. Black robes could be Theurges of the Death Domain, Red robes the Trickery Domain and White robes the Light domain. This favors the fact that in DL, the mages seems to draw power from a divine entity, blurring the lines between mages and cleric. True cleric like Goldmoon could be Favored Souls (UA) with different domains.
2) I second the warlock ideas. Lunitari, Nuitari and Solinari are all mentioned as being ''patrons'' of the different orders. I would remove the Blade boon, keeping Tome, Chain and Star chain.
Lunitari: Seeker (UA) pact
Solinari: Undying light (UA) pact
Nuitari: Undying (SCAG) pact