Mini Truck axle is OK, several people have used it, but it has crap for brakes (if your rig will see much road/highway duty or ANY towing). It is also a few inches shorter than your rear axle, so will require spacers to have the correct track width. The stock mini truck birfs are also not the strongest. You might be OK on 35's, but if I were running that axle, I would invest in some Longfields.
There are currently two solutions that I know of to this problem:
Hellfire Knuckles (they replace the entire factory knuckle with a cast unit that is set up for a steering arm bolted to the top
Slee High Steer arms, which bolt to the top of the factory 80-series knuckles and run a bit long bolt between that arm and the stock arm below in double-shear to make the arm strong enough to mount your steering hardware to (the slee upper arm only attaches by 3 bolts, so not enough beef to run the top arm by itself)