Decks that rely on fast mana, like combo decks, can go as low as 14 lands, as they make use of mana rocks like Lotus Petal or cards like Dark Ritual to add mana and cast as many spells as they can to execute their combo
Pretty much every cEDH deck is playing these cards anyway, so it shouldnt be hard to protect your critical spells in a Shadow deck
Still, with all of the sets synergies, Retrieve the Esper may find a good home
Having an instant-speed commander in the command zone is quite nice for a mono-blue deck, and you dont even need to have all that many Moonfolk in your deck to take advantage of that ability
Tolsimir, Midnights Light As long as you attack with Tolsimir, Midnight's Light and any wolf creature, you can choose an opponents creature thatll block that wolf