Unfortunately that hotel is not on the OP's list (Category A).

I think all of the hotels are somewhat the same (they are 2-3 star hotels. I've personally stayed only at the Furama in the past); since this is a stopover, perhaps the main criteria would be proximity to the MRT or in an interesting neighborhood, and not so much the quality of the hotel

That rules out the Copthorne Orchid - it is away from the city. Perhaps that rules out Hotel Royal at Newton as well - it is on the fringe of the CBD with only the Newton Circus hawker center nearby.

The Furama is in the Chinatown area - you might like it if that's what you are looking for. Near Outram MRT.

Royal@Queens and Allson are near each other in the Bras Basah area - close walk to the City Hall MRT station. I like this area - Chijmes nearby, a 24-hour food court at Bras Basah, the Art Museum at the old SJI school building, walking distance to Little India etc.

Peninsula is an older hotel in the City Hall MRT area. Nice walk at night to Boat Quay - you'll walk past all the historic buildings of Singapore. I think this has the best location.

So you choices would be:
a) Do you want to be in the colonial-era historic "center" of Singapore (Peninsula). Minus: Tired hotel.

b) Do you want to be near Little India, Bugis (and the same time near the City Hall MRT) and some art museums plus have lots of eating options? (Allson or Royal@Queens).

c) Do you want to be in Chinatown? Then the Furama.