New axle new bearings, seals too. No way you are going to get the bearing off and use it again; also the bearing on the axle you will be getting is different to the one on your truck now.

It will take longer than an hour since you will have to take apart your old axle to get the brake off. There is a pretty good write up in the maintenance section of this website. I could not get the rings or bearing off the axles by banging or pressing and had to resort to a grinder and chisel.

The parts list says you need a different bearing case, which is pretty important as it holds the axle into the tube. I am sure the axle is significantly different because the inside of the bearing is wider so the snap ring groove must be in a different position. However the axle is [should be] the same length and the outer race of the new bearing has the same dimensions, what has changed in the bearing case? Both of them bolt onto this axle housing.

Timken has the bearing, it might come with the ABS ring, retaining ring, and/or snap ring, you can see pictures on rockauto, I think the big bearing is listed for 98 T100.

There are some parts on the flange end of the axle: lug bolts, deflector plate and a thick paper gasket. Pressing the lug bolts out ruins the deflector plate. If you get a used axle leave all this alone and use it as is. There is no reason to get new bolts unless one is bent or something and if you see bent bolts on a used axle you should pass on it.

Everyone has a different way to deal with the dripping brake line so I will share mine too. I cut the finger off a latex glove and shove half a Q tip into the hole.

If you jack up one side of the axle at a time to work on, oil will not drip out. If it is level there is a ridge just inside the tube that keeps most of the oil in. This ridge also props up the axle so it doesn't sit on the seal if it is unbolted and hanging out a little.