I have found I need less light in my paludarium than in fully submerged aquascapes. The leaves closer to the light tend to brown unless I close the vents a bit. Being your tank will have humidity from the water, it will not have too much humidity being its open topped. I have 2 36" two bulb t5no fixtures spaning the 6ft. I feel like I just make it I am going to add a single 48" t5ho I have around to the center and give a 1-2 hr noon burst to get things to perk up a bit. Soon as I get the chance to wire it up. Their are various swords, ludwigia, anubias, Syngonium podophyllum and chain sword grass. All alive and healthy, but not where I want them.
Peace lilies as all spathiphyllum are low light plants that do well with here and their direct sun. Med light would probably be best for your set up.
Search t2 lighting. T2 is newer tech than t5. It gives off alotta light in a little package. They are getting very popular in the hydroponic world. Especially because they sell ones on telescopic snake arms The bulbs look like an unsharpened pencil painted white, and are blinding when turned on. This would probably fit nice for you being it seems like your trying to set up a focal point in your home decor. The small powerfully light will make your lillies the focus not the giant light.