I haven't gone through all the recent posts but I want to point out that some years back I posted a step by step of leather saddle restoration instruction. I stand by it . If a saddle can be revived this is the way to do.
Two statements I noticed need challenged.
1/ Brooks Proofide does soften leather & you can over do it. It is the best thing for a saddle that is clean and dry and not totally cooked. Too much Proofide on a new saddle will soften it prematurely.
2/ Saddle soap along with sun & sweat is a saddle's natural enemy. There are better leather cleaners. Try Lexol Leather Cleaner. Saddle soap drys leather. The best way to wreck a saddle is to rub-coat it with saddle-soap.