You said that the fluid on the outside of your rim that you stuck your finger in smelled bad. What did it smell like? Was it a very strong petroleum smell?

If so, I'm assuming that it's from the front differential but I don't know how it would get on the outside of the rim without getting all over the inside as well.

None of the other fluids mentioned have that strong of a smell (power steering, brake fluid, bearing grease (either front bearings or CVs)).

If I were you, I would do the following in this order:

Check fluid level in front pumpkin

Jack up vehicle (wheel with suspect leak) & shake wheel top to bottom to see if bearing is shot.

Check CVs again but not just for split boots, also check to see if you can determine if grease is getting out past the bands at each end of each boot.

Check other fluids (brake, power steering) to see if level is low or if the smell is similar.