drudy
I have the mustang 8.8 from an 86 GT in my 66. Yes, the axel swap is pretty straight forward. I can't remember exactly what year ranger I used, but I used one ranger axel and one aerostar axle. The reason for this was that I wanted to keep the axles on the same side that they had been driven for thousands of miles. The brakes would likely work but, I chose to use cobra disc conversion from "North race cars" you can google the company. The ranger brakes are drum and kind of small. It's similar to the MS swap but for the 8.8 axle. I believe that the explorer axles are a 31 spline count. The explorer center section is offset and the fox is centered. I found the info for this swap, I think it was CarCraft magazine online. There was also a source in the article for the spring perches to fit the 8.8 axle. It's been a couple of years since I did the axle swap, but the info is on the web. Many people have done the 4 lug to 5 lug swaps on the fox mustangs.
Good luck!

Try google for many of your questions.  I fouind one Ranger site that shows that the Explorer axles are 31 spine and not 28 spline that would have come with the Ranger or Mustang.  Good suggestion above on left and right axles and direction of rotation.  So the Explorer swap will not work unless you also went for the carrier and now you are into a lot of work.  See this site:

http://www.therangerstation.com/tech_library/Axles.html

 

The earlier Rangers had 28-spline axles. I'm just going on memory but I want to say Ranger axles up to about '92 were 28-splines, before 31-spline became standard.