That low tech show and tell thread was also my inspiration. I got lots of ideas from there. I like your plan for a low tech tank. You probably dont even need liquid co2 if the tank is going to be heavily planted and a bit overgrown like you mentioned. Some flourish comprehensive should be great for your tank. That is all I use.
The lighting is definitely tricky for that tank. I'm not sure the exact dimensions for that tank, but judging from the picture, you should probably use a t5 fixture, but raise it up to make it lower-medium light as well and getting even coverage from front to back of the tank. You can also check out my journal in my signature for any plants that I recommend for low tech. They all are doing great in my tank