All this is "picking the fly s**t out of the pepper."
Leather saddles don't really need to be conditioned until they need to be conditioned. That can be out there a decade or more, depending upon local weather and riding environment. All this stuff is good to use - up to a point of excess. Just don't over do it, and you won't go wrong.
The amount of Proofide that goes onto a saddle is about the same as you would use to shine your shoes. It has minimal effect upon the leather if used according to Brooks' instructions.
Getting a saddle soaked will not cause it to fail early. Riding a soaked saddle may very well accomplish that.
I don't know anything about long term care of leather saddles other then what Brooks instructions say. My Swift is 5 years old and my B17 is 5 months old and neither show signs of drying. I still go by what Brooks says, their the experts, they've been making saddles for over 100 years so I can only assume they know how to treat their saddles the best.
I keep my saddles covered in the rain even though I use Proofide and the leather may be somewhat tolerant of rain; I've have a little over $600 total invested in these two saddles (both have ti rails) so I'm going to keep them covered in rain and use Brooks method to treat them. If I get 20 years plus life out of them I'll be thrilled!!