I am doing the same kind of research as you are right now, and what I am finding is most recommend metal halide and t5 actinic lights for anemones.
As for you filter, I think it is more important to ensure you have flow throughout you entire aquarium. Most people with smaller tanks put a powerhead on either side of their tank, but maybe for you, since you have an HOB
filter already pushing a lot of water, you could get away with only one powerhead to ensure you have different levels of movement throughout the tank. Remember that different corals require different amounts of flow so you have to experiment with what works best.