If you dont mind the bulk of the Fives, you can consider Elipson Facet 6B which I think is a better overall speaker than Fives. Sonic Sound sells it at same price as Fives.
Anyway, you don’t have to strictly use Klipsch 10” sub with the Fives, can plug in any brand and size of your choice like Wharfedale, JbL or Yamaha. Saw Lazada got one Tannoy sub at $150.
if you want small footprint then the Elac with sub of your choice would definitely be superior to Promedia Heritage. Call Alpha in advance and ask them to set it up with a sub to hear how it sound in 2.1 configuration.