Your more than welcome and I'm sincerely hoping that things work out to your satisfaction. As I mentioned in a previous post, much of what your doing now is going to take eyeball measurements. The hood opening will take cross measurements before you do your final bolt down (sorry I can't make out the measurements in the pictures because of glare). Align the front sub-frame to the body, even by eye now because, your firewall, and A pillar have been pulled to allow door gaps...your rear frame rail measurements are out the window because of the difference in your "O" to "J" measurements. By keeping the front sub-frame semi loose, it should be easier to move it forward or backwards if needed. Gaps are going to be an "I can live with that" type of a situation. It will be a situation that may get frustrating but keep at it, a little here, a little there and you can get results that hopefully you can live with.
As far as the tracking issue goes, I would say it is hard to tell with 100% certainty, but chances are if you have the rear end bolted into the original mounting spots, it will track sideways...It probably did when you bought it, but, who looks at rear differential spacing's in a wheel well? Not many people.
I'm glad to hear your on a track that will give you better results and again, I hope that in the end, they are acceptable. Any other questions, we'll be happy to help if we can.
Best to you