I love the look of your tank! And I am probably going to totally steal your idea about lighting with a floor stand because . . .
I found this post looking for information about cats and open-top aquariums. We have always kept a hood on our 30gal to keep the cats out, but I hate the look and the light is terrible. My husband and I want to keep it open and have a light hovering over it, but we have six cats! They already jump on the hood and drink the water through the openings. Our kitten even jumped into the aquarium (and right back out!) once during a water change. We had a glass-top first, which we kept on for about thirty minutes when it quickly became clear that it was going to break very soon. Also, the cats like to paw at the glass when the fish are especially active right next to the glass, like during a cory mating dance.
Your floor lamp solution is great especially because I have been worried that the legs on those table-shaped fixtures would break causing the light to fall in the water, or that the cats would rip a hanging fixture right out of the ceiling. Since we rent, I am also hesitant about putting holes in the ceiling and don't know much about its structural soundness.
Do you have any more experience with cat-proof lighting for planted aquariums? Do your cats reach into the water and harass the fish? I noticed your tank is on a table with an edge large enough for a cat to sit on, whereas our tank is a stand without much of an edge. I'm with you and don't mind the cats drinking the water. After all, if the dissolved nitrogen compounds and minerals are safe for fish, it's certainly safe for cats. However, is aquarium water so delicious that if we don't give them an edge from which they can easily drink it, are they going to keep trying to get at it other ways?
I'm not surprised at your experience with your otos and corys. Ours hid almost all day or, in the case of the otos, held very still all day until we put them with our gouramis and platies in the bigger tank. I think the shyness reduction thing is like a feedback loop, because the gouramis and platys also became more outgoing and active.
Since you asked for constructive criticism, the first suggestion I have is that because it does merge so seamlessly into the room and even the outdoors beyond the window, which is absolutely lovely all together, is to add a very subtle hint of contrasting color around your focal point, tracking the diagonal of your pennywort, to give the eye more of a path between indoors, aquarium, and outdoors. Maybe a couple stems of differing lengths of a pinkish-green rotala or one of the reddish crypts next to a slightly shorter one near the small piece of wood on the right. The other is that since you have such a cool contrast of light and dark, why not give the base of the java ferns some broader low soft shadowy texture with moss and maybe small anubias, and maximize your bright greens and wild textures in the light area? The latter will allow the addition of proportionately more visual-flow-enhancing color additions, and I think you have sufficient dark green there already to unify the tank.
I'd love to hear more about your experience with your beautiful open-top aquarium and particularly how your cats deal with it! It really does look like a little visual breath of fresh air.