3-screw Warn Automatic Hub Locks (
F6TZ-1K105-AA)
Regarding part #3: I think the double-lip faces INboard (toward the diff) so that if pressure is higher OUTside the hub (deep water), the double-lip will expand slightly, forming a tighter seal against the axleshaft & spindle bearing race.
But that's just a guess.
Before the small outboard snap ring (18 in this diagram) can be installed, the stub shaft must be pushed fully outboard against the inner spindle seal by reaching behind the steering knuckle to the u-joint.