I have a 96 F150 4X4 with a Dana 44 front axle. I'm going to replace the bearings (inner/outer bearings with racers, as well as the oil seal). While I'm in there, should I replace the needle bearing and seal as well? How hard is it and do those fail very often? Is it worth it?

 

Well, its hard to say. Seals dry out allowing water and dirt into needle bearing so if it was me I would. Only about 30 bucks more for the assurance that they're GTG.

 

To remove that bearing, get yourself a slide hammer (you can rent one at an auto parts store) and a pilot bearing puller like this:
OTC Pilot Bearing Puller, 6 In L - G4458492 at Zoro
I got one from Autozone for about $15.

Then remove the bearing like this guy did in this video (fast forward to the 9:00 mark):