They will go into the 8.8, but the 94-98 Mustang axles are .75 inch longer than those of the 87-93. So it's gonna move your wheels out that far on each side and force you to use the rear brakes from a 94-98 Mustang as well because the longer axles will not bolt up to the Fox Drums.
Yep, direct fit as the housings are exactly the same, but as said above you will need the brake hardware too. A good site to read on the conversion is.