Planted Tank Project

I wouldn't fiddle with CO₂. It's only necessary if you want an aquascaped tank with difficult plants and very few fish, and those are not minimum of hassle. If you have normal numbers of fish, they will produce easily enough CO₂ for the plants.
I'd get your plants from EBay, much cheaper than shops. Don't buy potted plants, get loose ones, either with roots or as stem plants, which are basically unrooted cuttings which will root in a few days in a decent substrate. Try a variety of plants, I've found that some do well in some tanks, but not in others, difficult to explain why. I've found absolutely no difference between T5 and T8 lighting, whatever people might say. I've also found that plants grow at least as well under normal white lighting as under so-called plant friendly lighta, and the fish look better as well.
Of course, as you are having mopani wood, do get Java fern to attach to it. I strongly recommend Sagittaria subulata as a short grassy plant which spreads quickly over the bottom to form a nice lawn effect. I started off with quite a lot of Hygrophila (two types) which grew quickly but gets untidy after a while and I've got rid of  a lot of it. Amazon Sword should do well in a tank of that size. Others I like are Rotala indica, Baccopa momnieri  and Limnophila sessiliflora.

I reckon the substrate would be fine. I really don't know much about filters, just have basic internal ones myself. But I wouldn't go for too high a flow rate as some plants don't really like it, most aquarium plants come from still or slow waters. Also, a heavily planted tank won't need excessive filtration, the plants will do a lot of the work of taking out the ammonia and nitrates.