Sounds great, I always wanted to try something like that, but either didn't have enough money or got distracted lol. But I AM Going with a horror-halloween theme for my boys tank, which will have lots of black with black sand ;)
I think if you have the dividers siliconed and have the water level low with a top on, then a female and male can be in the same tank. I had 2 males and a female in a divided 10 gallon and no one ever tried to jump, and even if they did they wouldn't be able to make it over. Good luck!