I have the Pro Comp 6" Kit. It's been installed for 10+ years now without issue. 125k miles on truck, 110k miles on the lift kit. Other than the rust, it's been a good kit.
Shocks... I have paired that with a set of Sway-A-Way (SAW) coilovers from PRG. They are similar to the Radflo's above, they are the extended length to compensate for the 6" lift. I wouldn't recommend anything other than the Radflo or Saw's. Greg @ PRG offers two different spring rate options with the SAW's. I chose the heavier spring, and have removed my anti-sway bar. I think it is the 700# spring setup (600# on the soft setup). These have been good shocks, although they do need a rebuild right now. I have no experience with the Radlfo stuff, it looks nice though, there have been reports of some "clunk" in the shock though I believe? Not sure, as I said, don't own em, just read about them on here. Also.. reserviors... nice to have sure. Must have? Not really. I dont' know what your budget is on the project. That is one area you can save a few bucks to put towards something else you need. The rezzy's do look pretty though.
Rear Shocks.... I have the ProComp MX6 Adjustable Rear Shocks, this was the second style of shock I've had since lifted. First, it was the white body Pro Comp shocks that came with lift kit. The same shocsk that come with every lift kit, other than a different sticker. They sucked. I then installed the Bilstein 5150 Series shocks. I cannot recommend those either. Continuous problems with leaking seals on them. It didnt' matter what I did. Installed shaft "up", installed shaft "down", I went through 4 shocks this way. then I changed to the ProComp MX6 Adjustable Rear Shocks 3 years ago, and have not had any leaking shock issues. I pissed around with the adjusters at first, but could never really feel any difference. I would recommend them as a less expensive option than the Radflo or SAW's on the back.
Definitely recommend the traction bars. You absolutely will tear out Transmission Mounts if you don't install one. I have a set of PRG "Street" Traction bars, and they are very beefy. They've been installed for about 6 years now. No issues, they just need re-powdercoated. His come with weld on mounts, so you'd need to have access to a welder to install the front mounts. I very much like the design of his rear brackets, as they are quite beefy, and are incorporated into the U-Bolt bottom bracket.
Upper Control Arms... a lot of guys have them. I do not. It's never been a huge deal for me. I have offroaded my truck, etc., without issue. Is there some interference? Sure. Hasn't caused me any issues though, other than an occassional bang. It never happens during normal driving though.
Other items to consider... the lift kits come with blocks. You could always install some different leaf springs instead. Deaver C-30 pack from PRG seems to be a popular option.
Tires... quick summary:
Pro Comp Mud Terrain, 35x12.50-17: 18k miles
Cooper Discoverer S/T, 35x12.50-17: 20k miles
Kumho Road Venture M/T, 35x12.50-18: 18k miles
Nitto Terra Grappler, 325/65R-18: 40k miles and still rolling
Good luck with your build.