Here are some articles in the link below, Glenn. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=900993&fpart=1
I think I have posted more links on the forums on this subject than what's in that thread if you care to search for them.
MolaKule or Bruce or anyone, correct me if I'm wrong anywhere below.
My answer to the lean burn question is that it increases the nitrous oxides and that increases the nitration of the motor oil which is a major cause of oil degradation. Lean burn also causes high combustion temps which will further degrade the oil in the ring belt (which is already well above bulk oil temp).
High combustion temps increases the reaction rate of the degradation reactions. Rule of thumb is that a reaction rate doubles for every 10C increase. Arrhenius Equation: http://en.wikipedia.org/wiki/Arrhenius%27_law
Detergents and dispersants are similar and there is some overlap of capabilities but generally common modern motor oil dispersants are better at keeping 'nasties' in suspension at low temperatures and detergents are better at it at high temperatures. Metallic-based detergents do the bulk of acid neutralizing and dispersants can do it but less so.
I'll pass on the other questions, at least for now. :)
One more link and it's a shame the pics have been taken down. Maybe they can be found through detective work. If not, the discussion is still good. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=803291#Post803291