How likely would it be for either scenario to work out -
  
  1. Couple getting approved for a second mortgage. Facts-
  -Couple in early 60s
  -Both work & are paid above min. Wadge, one full time one part time
  -Still have 20 yrs left on current mortgage
  -Excellent credit score (above 750 each)
  -Plan to rent home to family member
  
  or 2. Persons above agree to co sign a mortgage loan with family member. Facts-
  -Other person has low credit score (below 550)
  
  What would the logistics of each scenario be?
  
  Thank you
  Added (1). House price would be $110,000
  Read more: Second Mortgage/Co Signer Mortgage Approval Potential?