Yes, I agree, given the choice between Catapults a la vanilla Civ were they are 1 Move per turn deadweights on my stacks, I'd prefer FfH2's inexpensive Mages with Haste and Fireball.
Anyway, so, ONLY recon units may receive hidden nationality, at random, from CoE cities. Got it.
So, that means the army, at full strength, consists of:
4 Beastmasters
4 Shadows
Azkalan
4 Shadow Riders (?)
Assassins and Rangers
<In open border situations, Priests of Leaves can offer passive support in the form of healing>
In the Civilopedia it lists the CoE symbol under requirements for Shadowriders, but does that mean it has to be my state religion or merely that the city building them has to have it?
And later on, Veil of Night gives Hidden Nationality to ALL my units. Seems simple enough.
The +1 strength to all Recon units will help offset the -X% city attack, and I use the Illusionist trait to weaken but not kill enemies in stacks for my Assassins to prey on for easy XP.
Any other cute quirks I'm missing?
EDIT:
Oh, I forgot Nightwatch. They're not Recon but they come with Hidden nationality at the start. Do I need CoE state religion or just a CoE city with an archery range?