1) For your first question, you have to check with HDB if the said shophouse is categorised as commercial or residential or both. If it is purely for commercial, you are eligible to purchase a resale under single scheme without needing to sell the shophouse.
2) As above.
3) You are eligible for singles frant and HDB loan providedyou only owned 1 commercial property and it is being used to for your own business purpose. In addition, could not derive any income from other sources. If you did not meet this requirement but want to take up a HDB loan or enjoy the Singles grant, you have to sell the commercial property first before buying a resale HDB. This requirement does not apply if you intent to take a bank loan and did not apply for any grants.
ERA Realty Network Pte Ltd