I have the RC 4" lift on mine and it's OK without the SYE, have a good driveline angle with the TC drop. Having said that I would still recommend an SYE and get rid of the drop if you can, really messes up your clearance. Good choice on the shocks, the RC ones, well, I don't like them.
I used the sway bars mounts that came with the kit until I could get adjustable bars but I would definitely recommend getting those. Get good quality adjustable bars, I went less expensive than the best (cheap) on my front bar (have an RE on the rear) and am paying the price, I'll be buying a better bar very soon.
Extended brake lines depend on how far you drop. My back line and right front when disconnected were stretched to the breaking point and I had to get longer lines. Try it and see.
You may not need the dropped pitman arm, it is a pain to get off anyway so try it first without it. (if you do decide to change it do yourself a favor, run down to the parts store and rent a puller).
Might get a new steering stabilizer while you're changing things down there.
Get an alignment after you're done.
Get some new, bigger tires and wheels, and then new flares, and then new bumpers to balance it out and then get new...
Sure I'm forgetting something but the only other thing I could think of that you might need now is some tools for the GF so she can install it. Don't want her using your tools ya know, she might break 'em or lose 'em. Maybe some cold beer and an umbrella, it can get hot watching someone work.
Good girl, she's a keeper