Added after 3 minutes
I think the Griffin Conservatories on U tiles should have troops corresponding not to the Castle of the player taking them, but to the terrain type of that zone!
upd. It's a shame the neutrals don't have a suitable 7th level creature in the Conservatory. .. Although! You could do this: minimum - 30% chance of getting 1 Faerie Dragon, 2nd - 30% Rust Dragon, etc.