For you purpose I would not suggest anything shorter than 7.6 feet and nothing over 9'. Ideally I would say roll with something between those two lengths. If you are looking for the one do it all fly rod I would suggest a 5 weight...With this not only could you hit the small streams, but if you ever wanted to head out and fish a larger river, lake, you could do it. Also, the 5 weight would be fine for smallmouth and largemouth bass if using lighter flies and techniques. If however, you solely plan to use this rod for small stream trout, I would say go with a 4 weight. 4 weights are wonderful. Once you get into 3 weights and lower your ability to handle any wind, cast with distance, and play fish without exhausting them to death decreases. It's all a matter of compromise. The 5 weight will be able to cast farther, cut wind better, cast larger flies, and play larger fish. But the 4 weight will have a more delicate presentation and be a lot more fun playing small fish. For an all around, small stream trout rod, I would say either a 7.6 or 8' 4 weight would be great. Pick something with a moderate to moderate fast action. Get the 2 or 3 weight as a "Fun rod" later.
TFO makes good rods but for just a little bit more you could get a lot better rod. I would suggest looking at the St. Croix Avid. They have an 8' 4 weight 4 piece that would be great. Model A804.4. Also check out the Orvis Clearwater II series. Otherwise the TFO will be fine.
WF or DT. Weight Forward is my choice. Double Taper is better for roll casting farther, and tends to have a more delicate presentation on the water. Also once you wear out the front part of the line you can just flip it around on your reel and you have a new line. However it won't handle wind, larger flies, and distance as well as WF. Again, compromises. I would say go WF and master that, then try DT. Regardless, just make sure you match the line weight to the rod. Also, color should not matter that much. If you get in a pool or river underwater and look up at fly lines, they mostly look the same color from below. In addition, trout usually spook at the sight of a fly line no matter what color. That's one part of your leaders job. A lot of people prefer super bright lines so they can track the line on the water and follow their casting visually easier. That said, I never have a problem seeing my line no matter what color and usually go with something neutral...Just because it doesn't feel right to me to be out in nature using colors that clash with everything. Hot pink kinda breaks my feel good nature vibe but that is just me. The lines you mentioned should be fine, I prefer the Scientific Anglers Trout Taper.
Leaders / Tippet: Most any name brand is good. Umqua, Rio, Orvis, etc. I suggest using knotless tapered leasders. For small stream fishing I would go with a 4X tapered leader, 9', and carry both a 4X and a 5X spool of tippet. After you've made a few fly changes on the 4X leader, shortening it by about 1.5 feet, tie a perfection loop in the end and then you can alternate tippets. You could either use the 4X tippet looped on with another perfection loop (Taking it back to about 9') or go to a 5X for a more delicate presentation. This would be fine as you would be going from a 4X to a 5X taper...Or staying with a 4X taper would be good too. For extremely picky fish, it might be good to use the same combo scheme...But with a 6X leader and spools of 6X and 7X tippet. Carry a few leaders as they can be lost / ruined easily especially when starting out.
Reel: Small stream, trout - Anything will do. It's just line storage really. You don't need anything fancy, just as long as you like the way it handles. The reel you listed looks fine...Put some backing on it and load it up with your new line. I like to have enough backing so that when the fly line is fully reeled in, it almost rubs on the reel housing, but doesn't.
Not sure about your skill level, but in person instruction really helps. There are also some great books out there I can suggest as well.