My only reservation about something like that vs getting a bumper fabbed with a swing out would be a substantial loss in departure angle with that sticking out of your receiver....
I do agree about moving the spare from the stock location though. Do you have room to strap it or bolt it somewhere in your bed? I forget what you've got going on in there...
Truck looks good.
FYI, the only difference between the Black Magics and the regular 500s is the black anti-scatter ring they put in there, it reflects within the housing with the light off making it appear dark but it's the same reflector and lens. My buddy had a pair and I had a pair of regular 500s, the light output was marginally better from the regular 500s but not enough so to negate the cool looks of the Black Magics.
The FF is a combo-beam, so it's got a spot portion that throws light way far down, and a flood portion that floods out. People mis-perceive that as hotspotting but it's an intentional design of the beam pattern, and I found my set-up of 2 500 driving and 2 FFs to be ideal for max coverage for minimum dollar 500s give a wide, even driving beam, the ffs help flood out the foreground and pitch a pencil beam *way* downrange to give you some serious distance on the straights. 4 Black Magics ain't a bad way to go though
I prefer staying away from HIDs because I use my lights on rural highways to suppliment my high-beams, I don't like waiting for HIDs to heat back up, and cycling them is hard on the bulbs. Other people here feel differently.
Truck is looking solid. Solid find on the FX4 axle. Makes the swap a lot easier. But as others said, do not use your old u-bolts. They're cheap to get bent up at a spring shop usually $50-100 (expensive to buy from the dealer @$50/ea). You're also going to want to retorque them several times over the course of a week or so. I suggest taking the opportunity to bump up to 9/16" ubolts as they're much stronger and shouldn't cost much more at the spring shop. Ask them what they recommend torquing them to (probably about 80-90lb/ft) and like I said, they stretch, you'll wanna retorque a few times. Just keep retorquing until you can't get any more turns on them. Check them every few days.
You're gonna love having the LSD back there though. Throw some fresh fluid in it and don't forget the friction modifier, you'll be impressed with what it can do for a stock LS. It will serve you more than well enough until you can afford to put whatever "real locker" you want back there. A little 2-foot action with the brake will help it engage harder at low speeds and essentially make it run like a spool. They're really a pretty bombproof diff. I've worked on several that had over 200,000km on them and still worked quite well and looked clean inside. If it's a disk brake axle too you're really in luck. The disks in the rear make such a difference in braking attitude and performance. No nose-dive and way more stopping power.
Billys are a good choice, but just as an fyi, the ProComp ProRunner shocks are supposed to be pretty much a clone of the 5100 and they're $100/ea. I got a set for a Chev 1500 (I'll check the PN later), they bolt in and fit at max compression, but have way more droop than stock. I pull 10" in the back limited by the driveshaft and then the rear spring shackle. Plus the valving for the heavier truck rides a lot smoother, especially with a loaded bed.
Supposedly the SportTrac springs sit a bit taller than the Expo leaves do, but they do both give you a lift. Skyjacker Softride springs are another option. The 4" ones will give you a slight lift and allow you to ditch the block. Plus they ride awesome, though I needed an add-a-leaf in my pack to hold everything I carry.