With the vertical-oriented design they're going for, Rocket Jumping would be a natural fit. Spending a chunk of health/armor to quickly get a bit higher than a double-jump, while still having your second jump for a further boost or correcting your path seems like it would have a lot of potential in both single and multiplayer. They're already designing the areas with a lot of verticality, slotting in Rocket Jumping shouldn't do much, if any harm.
Bunnyhopping, though? Nah, the game is clearly designed around its current lateral movement speed, with lots of overlaid narrower paths instead of fewer wider ones. I feel it would be too cumbersome to get much use out of it, especially if the alpha map is anything to go by, it'd be too hard to avoid careening over those railings and into the lava. Bunnyhopping in a game with a double jump also adds another layer of complication.