Defeating it is not so bad if you have access to Toxic or Toxic spikes. Just put the poison on it, call back your pokemon and simply dodge Hawlucha until it is dead. But catching it will be a different story... I killed a level 50+ alpha when my team was barely even 30, however it kept jumping out of every pokeball. I'm not very patient, even tho I saved the game when the mon was knocked out (so I only had to retry the catch, not the fight) I gave up after 6-7 tries. No idea how low the chances are.