While borates cannot be used with catechol and pyrogallol, pyrophosphates are ok.
Don't worry about any of the extra ingredients in Dektol and other commercial versions of developers. Kodak is not hiding a magical ingredient from the user. Some "extras" are used to achieve a stable powder mix, others to help the stabilility of the mixed developer, etc. For example, Microdol contained an antisludging agent.
Gordon Hutchins chose metaborate for his PMK formula, so I guess he went against that advice.
The extra ingredients in packaged developers don't worry me, I was just curious to know more about them. Thanks Gerald.