Well, to be honest I don't think the second tank stock list will work long term either, especially if the red devil is a male. Maybe you will have some luck, but my prediction will be conflict between the texas, cuban, and RD once the fish are mature.
If you often find you are very busy and can't do water changes regularly, overstocking is probably going to be a disaster in that situation. If you had to go a month without water changes when the fish are adults, they are going to start having health problems, particularly the Oscar which will develop Hole in the head disease/HLLE. They really need very clean water, and an overstocked tank with weak maintenance schedule is a recipe for a sick fish.
Your best bet would be to sell off about half of your fish to be honest, both setups will not be sustainable long term. For a while you will be OK but not for a permanent situation.