new to plants, a few questions

That is a lot of flow for a 20 gallon tank. Not sure if plants would do well with all that current. Most plants take up nutrients through their root system. The plants listed are easy to grow. The amazon sword is a heavy root feeder. 12 hour photo period should be fine for the plants. If you develop an algae problem, cut down on the hours of light.

I'm not real experienced in plants but have 3 types of plants in a tank now (duckweed, java moss, Brazilian pennywort), all different from the plants you've chosen as mine are floating plants. However, there's some crossover knowledge I learned that can benefit you. I'm pretty sure all or most the plants you listed are substrate feeders. You'll likely need some type of ferts in the soil if I'm not mistaken. Depending on how much iron is in your water, you would likely have to add iron to the water as well. My plants did ok for 2-3 days and then started to yellow around the edges. I got an iron supplement/additive and revived them (only to burn them some by adding too much). The plants I'm growing, they are growing very well and I have the lights on no longer than 8 hours. I just have to get the iron measured better, it's hard to measure using a cap for the bottle like suggested, and getting exact dosage right. I also did have jungle vals in another tank about a year ago. They did ok, but the lighting wasn't enough and I needed iron additives for that too, but they died anyhow. Lighting, you're gonna want something within a certain wavelength/spectrum for it do anything for the plants. I believe something 6500k is the standard/average for a low to medium lighted tank....I'm sure someone with better understanding of lighting will chime in and help there.

I think you'll definitely need a better light to start, along with some plant food/ferts. I hope this helps some.