Your restrictions pretty much decide half of it already, so here’s the only choices available:
2 Lords - A level 4 magic caster is a must, and I’d go with a combat guy rather than a BC lord.
4 Heroes - HG, BC, Sorc and CD Hero. Pretty standard, although I’d give the sorcerer options to help war machines.
All sorc characters can be mounted on/with any war machine which they can give bonuses to or use to move around on.
2 Core - I guess that is not up for an option then
6 Special - Monstrous Infantry and 3 war machines - Big golems. Rocket launcher, chariot-style charging machine (here’s your train), something similar to a repeater bolt thrower for the HGs but with a LOT of bolts on it
5 Rare - 2 monsters and 1 warmachine - Mega golem with a lava upgrade, earthshaker-style war machine. Final monster is a tough one, something like a Kolossus although I’m not sure if that counts as a war machine or a monster.
Sorcerer Lord with Lammasu and Palanquin mount options
Zhatan the Black on Taurus
Sorcerer (can upgrade to Master Daemonsmith)
Slavemaster (CD Hero, quells animosity and allows inclusion of more slave units)
Tauruk <br>Hobgoblin Khan<br><br>CD Warriors (shields, blunderbusses or great weapons) <br>Hobgoblins (Bows and/or additional hand weapons, upgrade one unit to Sneaky Gits making them scouting skirmishers with options for poison, can upgrade one more unit per Hobgoblin Khan in the army but can never have more Sneaky Git units than regular Hobgoblin units) <br><br>Immortals (CD Warrior kit with alternative heads and weapons sprue, bodyguard rule interacts with Sorcerer Lord, Ensorcelled Weapons) <br>Bull Centaurs (fast hammer) <br>War Golems (slow anvil, magic resistant) <br>Magma Cannon, Deathshrieker (I really like those 2 war machine types, add Daemonsmith Engineer additional crew option) <br>Tenderiser, spiky whirling-death contraption (like The Cleaner` in Labyrinth but bigger :)).
Delving Engine (Hellcannon-like subterranean drill-tank piloted by a Daemonsmith that can deep strike, possibly carrying a small unit of CDs).
2 Lords Fighting hero and magician. The lord can ride Taurus, the magician can ride… the Zeppellin (see rare entries)
4 Heroes (including 1 Hobgoblin and one BC) cd hero (BSB option), bull centaur hero, hellsmith (engineer and magician with special effects on war machines) and hobgoblin hero (can ride a wolf)
2 Core (1 CD 1 Hobgoblin) cd infantry, infernal guard is fine but with decent blunderbuss options. I do not care about fireglaves. Hobgoblins, sprue with hand weapon/shield and bow options.
6 Special (1 CD, BC, Monstrous Infantry and 3 war machines) Immortals (a simple sprue to convert Infernal guard into Immortals). Bull centaurs, Authomatons with bound in daemons FTW!, Death rockets and a crazy, very random effect, prone to misfire hobgoblin warmachine!
5 Rare (Hobgoblin wolves, Hellcannon, 2 monsters and 1 warmachine). hobgoblin wolf riders (cheaper!), Hellcannon, Giant fire golem, the ZEPPELLIN! (flying baloon filled with guns!), and finall something that cannot miss in a Cd army: huge mortar of doom!!!
As you can see we have only one Chaos Dwarf unit and one sprue of hobgoblins.
I’d love to include Orcs into the list, as I’m a 5th edition lover, but i know this is not the actual FW/GW policy anymore to mix armies…
It would be a nice otpion is a magician can ride a ZEPPELLIN and bomb enemies from above… droool! I can even get rid of the Lammasu!