i've learned a lot about the FD in the process of this swap, but I'm still wondering what the pilot bearing and seal function as?

 

the tip of input shaft of the Transmission "rides" the bearing in that "hole"

 

So what is the seal for then? I don't think I noticed any oil inside the "hole"

 

It's not sealing anything in...well it might help keep grease in the bearing. But it's primarily a dust seal to the outside from the clutch.

 

the pilot bearing keeps the input shaft on the trans center and does not allow axial movement of the input shaft, thus saving the trans bearings some wear. the seal is what it is, a grease seal. the pilot bearing is like any other bearing, it needs grease to work properly and not chew up the input shaft. th eseal keeps the grease in the eccentric shaft's dish for the bearing and keeps the grease from spinning out of the pilot bearing onto the pressure plate or clutch disc.