Have you tried editing "GameBalanceArtefact.txt" I think you can enable or disable buildings.
Edit: Try the GameBalanceArtefact.txt I included. I can't test it out on this computer (Graphics Card doesn't support Pixel Shader). I can't test it until i can use my other computer.
You might be able to do so by creating a new challenge file to force the sencond creature to act like tyke. See http://www.bwgarage.net/?pagerequest=edit_script for info on how to do so, if it's possible.