We don't sell the pre packaged aquarium kits for a reason. They are almost always insufficient in some way. Deluxe or not.
I looked up the 20 deluxe online and it comes with a plastic hood, single bulb strip light, and a whisper power filter. The light is 20 watts so it will not be enough to support a planted tank of the form you have now, and the plastic hood does not allow you any space to add a second fluorescent or a higher wattage compact fluorescent or t5 set up. Ideally you want to aim for 2.5 to 3 watts per gallon. The filter is fine for moving the water, but whispers, in my opinion, are not good bacterial filters. They have only limited media volume (the white pad insert that carries charcoal inside) and it is difficult to clean it without destroying your bacterial culture.
You could make this work for plants such as anubias and java ferns, but given the interest you have shown in heavily planted tanks and difficult little fish, you would be much better off getting a different set up.
We can set you up with a 20 gallon tank, glass hood, small compact fluorescent or t5 lighting system, and an aqua clear filter or small canister filter, and all the rest of it. I think you will be happier with a good set up.
-Sam