IF it had a lot of shade and depending on location, along with deep overhangs and a more thermal mass form somethign like real stucco (not that fake junk) or tile floors, it could probably get away with 2.5 ot 2 tons. But without knowing locations and total window area and solar gain, it's a guessing game. Interesting ot seperate heating and cooling system. Seems like it would have made sense to use a 5 ton water to water chiller with a heat pump mode instead. IF you already have a water to water heater, you have everything in place ot do both.
At some point, that's what i don't understand. These units have these desuperheaters but for some reason that industry is reluctant ot move towards chilled water. Yes, you'd need a storage tank and another pump, but equipment performance and effciency overall would improve and you gain so mcuh in what yo u can do for dehumidification and controlling systme capacity.