When I was researching this subject for the purpose of defining many of the terms you mentioned for the forum's Pizza Glossary at http://www.pizzamaking.com/pizza_glossary.html
, which you may want to examine, I was confronted by so much confusion and misuse of the terms, with a lot of overlap and blurry lines, that it made my head spin. To this day, I am not sure that I got the definitions right in the Pizza Glossary.
I started with the notion that preferments were commercially leavened compositions, including poolish, sponge, biga, and old dough (with pate fermentee
forms). Once made, these preferments should speed up the dough making process and contribute significantly to the flavor profile of the finished crust. Then I learned that it was possible to have naturally leavened preferments, including poolish, biga and old dough ("pre-fermented" dough). These preferments apparently serve the same purpose but may not act as fast or be as easy to manage as their commercially leavened counterparts, especially in a home setting. Some people also draw a distinction between a natural starter used principally for leavening purposes as opposed to using a larger amount to achieve other objectives, such as increased acid production and dough strengthening. For example, member pizzanapoletana (Marco) uses what he calls a "Crisceto" (naturally leavened) in an amount that is from 1-5% of the formula water. Beyond that, he believes and says that you are into bread territory.
Over the past year or two, I have tried to treat preferments mostly by their hydration levels, ingredient quantities, amounts used, and fermentation method. My "bible" for this purpose is articles by Didier Rosada, formerly an instructor at the San Francisco Baking Institute and a highly regarded classically trained French baker, at http://web.archive.org/web/20040814193817/cafemeetingplace.com/archives/food3_apr2004.htm
and at http://web.archive.org/web/20050829015510/www.cafemeetingplace.com/archives/food4_dec2004.htm
. I have also been influenced by Professor Raymond Calvel, a renowned expert in French baking and the father of the autolyse method. Since Rosada mentioned Calvel in one of his articles, he no doubt was influenced by the teachings of Professor Calvel.