All of the drivers you linked to have easy to drive 4 ohm or higher loads. The NP1 should be more than happy driving any of these directly, which seems will be the case with the fully active Linkwitz LX521.4.
Without additional information regarding the "passive L&C crossover in the LX521 top baffle" of this (older?) version of the speaker that is also mentioned in one of your links, we can't say for sure whether this will also be the case for that system.
For your bass section, we don't currently offer an amplifier that's suitable for delivering sustained high power into 2 ohm loads.