I am faced with landing at around 5am in CCU on a Qatar Airways flight, and my onwards flight to BKK is at around midnight. If I paid for the previous night at the hotel (Oberoi Grand), my hotel pickup would be waiting for me when I arrive. Then I can leave my bags at the hotel (not going to leave them at airport!) and go exploring for 6hr or so in the city.

I want to fleetingly visit

Belur Math
Eden Gardens Park (not the stadium)
South Park Street cemetery
Victoria Memorial
Mother House

Does my plans sound doable?