Great work editing etc and the best place to start is by examining the 10 year old Modded Armies of DOC111. Thorgrim and Icle's Armies contain all Single Player Campaign units, Steam Tank, Dread King, Carleson's Cav, Nagesh/Charriots.(The Charriots can be fixed by providing them with a Portrait, as far as other members tests showed) etc..but in my experience the game may sometimes crash when using them, if it has to calculate it moving and casting a spell (Nagesh) at the same time as being hit etc, too much going on but that can occur when using Mages etc.A Great Unit in DOC111 was also Morglum NeckSnapper, a Lone Boar Rider that has Morks Banner, permanently attached to him, at no extra Cost, ideal as a Mage Hunter, since he is much more manoeuvrable than a whole Troop of Boars.
As for Mixed Magic, Lord Volkmar and his Escort have both GreenSkin 'Ere We Go and Bright Wizard's FireBall. You may find that our Stats Editors may have trouble examining this Unit, since the Mixed Magic has been assigned using a Hex Editor, rather Wh2/3Edit. However, it's been a while since I last investigated Mixed Magic, as Villetrentmeth and myself used to play 63000gc Battles with these DOC111 Armies (with movable Artillary, see wiki for my Destructable Wals idea), for fun and here are some pictures from DOC111 and Villetrentmeth's own attempt at Modding Mixed Magic. Notice that in DOC111 the enlarged numbers/ranks of troops are given a Leader, so possibility for Berhardt to feature in Multiplayer, perhaps with the Grudgebringer sword attached etc, for future projects.
Whilst doing some recent tests I remembered that when I have mutiple units of the same kind, the banners become numbered 1-10. We would all agree that this is yet another fine detail of Dark Omen at work but I noticed that when a unit cried out for Help it was impossible to know which, as the 3d Portrait didn't have a number to represent the unit to go to. This was my initial reaction and so I'm not sure if there is another way to tell (I checked the map) and also no specific banner would flash as a warning.
Therefore I think these considerations would enhance any RTT but I do appreciate the particular circumstances that it becomes beneficial but increases with larger amounts of Battlefield Troops.