For Better or Worse (2) - S3-E29
Other mistake: When Loren confronts Elizabeth about giving Dr. Mike away, he states he's lived for 10 years with the guilt of not giving his late daughter Abagail away in marriage to Sully. But it would in fact have been only 4 years, given Sully's marriage to Abagail was 1.5 years before their pregnancy, labour, and death, followed by Dr. Mike's arrival a year later, to their current wedding day.
For Better or Worse (2) - S3-E29
Other mistake: Cloud Dancing gives Sully his white Cheyenne tribal dress to wear as a wedding suit, but Sully pulls on a very different deerskin coat inside the barbershop.
Answer: A Cooper was someone who made various things out of wood including wooden caskets and even barrels.