Guess this means you found somebody to do the work.
It almost looks like water got in the rear. Rear end oil should not be foamy like that. A lot of times that means there is water in. With that being said...
I would inspect what caused the spider gear to break like that. Its only on rare occasions that they break. Was the slide pin and bolt still intact? Pay close attention to all of your bearings. On second thought, all of them will require replacement since there was alot of metallic flakes in the fluid. Bearings are now contaminated. If you are doing all of the work yourself, pay close attention to everything and see if you can find what caused the gears to break. Sorry if I am repetive about it but spider gears are not common about breaking especially in a auto car.
Yes you can buy just spider gears but you MAY have to buy them from Ford. Actually it probably easier and cheaper to buy another 8.8 tracloc from gefracing since your clutch packs will need to be redone as well. You can buy the whole unit from them for around $250