I put a crayfish I caught in my 125 gallon tank. He was very selective. He went to every Hydrocotyle verticillata stem in my tank and chopped them off at the base. The Hydrocotyle roots finally died from this. As far as I know the crayfish did not attack any of the other types of plants.
I would definitely try a few cheap plants. He probably won't hurt them.
I was thinking extra vals, sags, wisteria and java fern. Maybe Java Moss or Riccia(floating). It really wouldn't matter if he destroyed or they died, because they would be surplus plants that I'm getting rid of anyway. But it'd be nice if he left some of them alone so the tank would look nice. Though the fake logs with plants attached would probably detract from the appearance anyway.