That idea's not gonna work unless you model them yourselves.
Remember what you're asking here. You're not just to use other people's work and you're PITTING them against each other. Knowing modders, they have pride in their work. So how are you going to balance them? Each mod got their own take on the stats and that makes the army behavior different in each game (if you've modded, you SHOULD have known this).

How are you going to appease each mod if you can't make them have similar stats? You'll get barraged by an entire mod team (or two) if you made their units appear weaker then the mod team's original plan. Or if their faction kept losing to or weaker than other mods' factions.