Tim...

My sense is that ALL of these suggestions are valid. If I were to put a wooden post in concrete, I definitely seal the bottom! But to be honest, I personally would not put wood into concrete. To me, a footing/pier/Strong-Tie plate or equivalent/wooden post would be the preferred approach.

I know many a person who has cut off and replaced the bottom of posts/studs...that were installed in a not-so-great manner and over time feel prey to Mother Nature.

Joel