The agency shall establish by regulation, adopted by the policy committee, standards for the eligibility of purchasers of housing subject to this part. Such individuals shall be first-time home buyers. Mortgages pursuant to this part cannot be used to acquire or replace an existing mortgage, except a mortgage which is security for a construction loan or a bridge loan or similar temporary initial financing. The purchaser shall be a resident of California. The qualified mortgage lender shall certify to the agency, in good faith, after prudent qualification of the purchaser that the purchaser is qualified under the provisions of this part. Section 51067 is not applicable to mortgage loans under this part.