Sunnats and aadaab of wudhu

Khilaal of the beard

Q:

  1. Is Khilal done with only the right hand or both the hand?
  2. Is the khilal done on all three parts of the beard or just on the chin?
  3. Even though the salaah is valid behind a faasiq (shave or trim the beard), is it Mustahab to repeat the salaah prayed?