How about changing the Imler/Imling partnerships so the Imler/Imling partners are the ones in the same column. Change the description to “boosts the Imler in the column directly above it” and “boosts the Imling in the column directly below it”. That way you don’t have to worry about people accidentally using more than 1 set of partners and losing the ability. They wouldn’t have completely overpowered stacking, but you could still put up to 3 pairs on your team. They would also be weak to column-type attacks.
Edit: Also on the subject of teams, Hound teams would be a lot easier to put together if the Blood Hound ability gave the entire team 1 minion instead of giving 1 creature 3 minions.