I have a complete Fusion 3 zone system. I love the fusion stereo, amp, and remote controls. I have the speakers just average at best. Go with the JL speakers, I hear good things about them.
Not sure what you mean by coax vs. component. If you are talking picture quality from the DVD player, definitely go with component, much better picture.
Good luck with the filter, I have never really had those work for me. Let us know how it turns out.
2008 Fountain 38' LX with Triple Verado 300s