OK you asked us to keep opinions to our self, but...You also wanted to know what to do about the death wobble.
I am home, canning some sketti sauce, so right now I have a little time. as pointed out above by snappy, you need an angle finder. The angle coming out of the T-case, and the angle at the pinion, should be the same if you ARE NOT using a CV type drive shaft. If you are using a CV style drive shaft, then the pinion should be pointed at the T case. BUT, the pinion angle is not what causes the death wobble, the caster and camber is. So with that said, the only way to correct that is to have it put on the machine to line it up correctly. That's where the upper control arm will come into play. ON a 4" lift, you can usually get by with a about a holes width difference. I have seen it done by oblonging the hole where it mounts to the unibody.(cheap) but it may come loose and go back to where it was with rough use. I have seen people ADD to the control arm after oblonging it, with 1/4 or 3/16 thick "washers" to gain the length. An easier and not too expensive way would to build a new adjustable control arm using thick wall tube and some heims or johnny style joints. Measure someone else's store bought arms to get the length you need.
BTW I am wondering why you need this to be able to go 42MPH. If I read correctly, it isn't tagged and insured. I have not seen a lot of trails where anyone would be going that fast. So that really shouldn't be an issue.
Also, the putting together of two different sets of control arms may not be something I would come up with, but...as you have it welded, a good(bad) bounce will cause it to peel down. If you all the way around, it would be much stronger.
On your Bumper:
The hooks should be reverse of the way you have them. Why? well if a hook breaks(before how you have the bumper mounted) the hook will fly upwards. Also, mounted in reverse, sure helps a strap loop stay on when it gets slack in it.
