Random Monsters Map Patcher – diverse neutral armies.

If the goal is to make an already properly trained system work, then it is necessary to have unit pairings in the database. But it is necessary to check how the AI will behave with them.
Although, I think it is enough to create a two-dimensional table, where the compatibility of units is determined, placing a weight in each cell - and already determine the fact of generation based on it. For pairings, the weight will be high, for the rest it will be equally low. The weight between good and evil races will be 0.

Added 12 minutes later

NCF will diversify things, as there is another upgrade there, which in total gives as many as 4 versions of each creature. In addition, some neutral creatures can be easily linked to the main races, for example, Enforcers --> Haven, Shamans --> Sylvan, Grave Robbers --> Necropolis.

This will be great for single-player, but for multiplayer, an abundance of imbalanced units is not good. By the way, yours can also be added ;) But you definitely need to increase their strength value for generation. And it is right that the creatures should be distributed among the races.