So last time it was discussed what the Ordo Xenos wouldn't have, or more specifically the Deathwatch Space Marine Chapter.
So in addition to what I suggested with the Chapter Council, what other non-codex formations would they have?
Well for one, their normal squads are essentially replaced with kill teams, which are super awesome veteran squads essentially. Special Weapons, Ammo, Heavy Weapons. All of it. This is a basic unit in the chapter, lead by a pretty sweet Captain/Librarian/Sergeant.
So seeing this as a basic unit, I think devastator squads and veteran squads are out. Maybe not vet squads, but really, it doesn't strike me as a battlefield formation that the DW would have.
Assault Squads, Bike Squads, Landspeeders, and Terminators are all still in. So are all Space Marine Tanks, except for maybe the Vindicator. How many sieges do they operate in?
So now that this is clarified, we see they only have 2 unique units really, the Kill Team and the Chapter Council as told of in Part One.
This leaves the rest of the army open to the Inquisition choices. Inquisitors, Assassins, Stormtroopers and allied units. Maybe the allied Guard will always get the Xeno-fighters doctrine BUT seeing as the IG codex is coming up for a re-vamp, this won't happen.
So here is the Breakdown
HQ: Inquisitor, DW Hero (Single Captain, Librarian, Chaplain), DW Chapter Council
Elites: Terminators, Inquisitor, Assassins
Troops: Kill Teams, Stormtroopers
Fast Attack: Landspeeders, Bikes, Assault Squad
Heavy Support: Land Raider, Predator, Whirlwind, Orbital Strike
Transports: Land Raider, Rhino, Razorback, Chimera
The only thing I see weak is the elites. Even Deamonhunters have one more choice there. BUT that shall be addressed in part 3.