They are all very different shoes. I'd recommend trying the different models on first to see which one fits best first as it may depend on your foot shape and running form a bit. Sizing between models can also change.
Conquest is by far the most firm (RMAT midsole) and stable (it also weighs several ounces more than the other ones).
The Huaka is totally different from the Conquest even though it does have the more firm RMAT. 2mm offset makes it very low profile and the RMAT midsole makes it very responsive. It does weigh about an ounce more than the Clifton (Clifton 1 at least) and the feel is totally different. Still, at 8.9 oz it is a great hybrid for smooth trails/dirt/pavement running.
The Clifton 2 was updated from the Clifton 1 and the update made it weigh about a half ounce more, firmed up the soft feel (some people would say it was too soft) of the midsole, thickened the tongue and beefed up the upper a tad. It made the width a bit more narrow in terms of fit.
Bondi 4 is a very nice neutral trainer....still a bit more on the heavier side (Compared to Clifton/Huaka) but fairly low profile and stack height (relative to other Hokas).
Hoka is coming out with 3 new road flats in the future (I've tested out the Tracer and the Clayton) and they are in the 7-8 ounce range, fairly low profile and feel faster than the Clifton 2.