VA appraisal typically stay with the borrower and not the house (unlike FHA). The appraisal is typically valid for 180 days or 6 months for the borrower on the house.
Yes. The Veterans Administration does not limit the number of VA mortgages a Active Duty, Veteran, National Gurad or Surviving Spouce may have. The only restriction to the number of mortgages is the amount of entitlement left for the borrower to use.