My trainer AI for whatever reason don't like using ice moves in battle. The type is properly defined in the types.txt. Wild pokemon knowing ice moves will use them at random still and the AI will only use them if they know no other moves regardless of skill. (For example an ace trainer with an abomasnow will use wood hammer on altaria over blizzard. Changing blizzard's type he uses the move over wood hammer.) I made a custom ice status move like hypnosis but for freezing but removing it from the moves.txt seems to do nothing. Otherwise I've touched nothing about the type or the trainer AI.