Not every single Rustys product is bad. I get so tired of people that spend so much of their time scaring people away from them. Rustys is a great place to get skid plates for your XJ, the coils are a quality product and you won't have any issues with them, and they are also a great place to get some other odd and end things that you have on your list such as brake lines, pitman arm, steering brace, etc.
As far as the trac bar goes, from what I have heard/read (correct me if I'm wrong) the Rusty's trac bar that you want to avoid is the one with the tie rod end, not the HD trac bar w/ body mount. I have the latter and is seems like it is a solid product. I have wheeled my XJ on some pretty rough trails since I've had that on there and had 0 issues. Perhaps I'm lucky, perhaps it's not such a hell-fire and brimstone product as some claim.
With regards to you manufacturing your own long arms, that's great. My friend and I made a custom y-link long arm setup for his XJ a couple of years back, and wow, what a job it was. I would also have to say that if you are qualified to make your own long arms, you should definitely just manufacture your own trac bar, but make it so that you mount it on top of the front axle instead of in the stock position at the bottom, especially with 8.5" of lift. You might not have really thought much about that, but it will improve the handling of your XJ.
As far as the rear leafs are concerned, I doubt there is a huge difference between the two company's leafs. If it were me, I would go with a small leaf as possible, and then the longest shackle that you can find to even up the front and rear. It will make your XJ ride smoother the flatter the arch of the leafs, and it will also flex better. You're hearing this from a guy that has experience with this. I have 8" lift leaf springs from Big Offroad in back and every time I go down a rough road I wish that I had a smaller arch. Too late for me to do anything about it now though. Anywho, I wish you the best of luck. Be prepared for long days while you build your setup and I hope to see some pics of your progress.