Welcome Carter. I don't know too much about lighting, but I too used to keep lights on in relation to the natural sun rise to sunset times, but I ended up having lots of diatoms/brown algae growth and then read some people recommend only 8 hours of light (guess it depends on amount of light and plant needs). There are "moonlight" lights that you can use for night time viewing that won't trigger photosynthesis in your plants and are dim enough that nocturnal fish will come out at night and you can actually see them. Or just schedule lights to turn on at times you are home.
But yes, you would need a much bigger tank to house the fish you plan on keeping. Even 1 arowana by itself at a big enough size is too big for that 65 gallon, same goes for just 1 RTC in the 65 gal. They might be okay at first, but will definitely need a much bigger tank fast. If not the fish will deform (external as well as internal organs will be cramped and shorten the life of the fish) and the bioload will likely be high in a tank that small for fish so large as well as possibly increased aggression from fish in a tightly cramped tank.
Research the fish you are thinking of keeping. Even bala sharks get large. If you can't upgrade to a much larger tank quick (especially if you get a silver arowana as they grow large really fast), then I would suggest sticking with the discus, angelfish and smaller tankmates. The Arowana, and RTC (maybe bala sharks too) actually fit under the monsterfish category and they get too large for a tank that size.