Let's correct some information here:
First - saccharomyces IS present in the lambic blend from Wyeast
I think Im missing your point on this one, no one was arguing that it wasnt?
Second - cooler fermentation temps are a good idea for most ales but this is a completely different animal. You have a complex mixture of different microbes that consume each other and consume byproducts from each other. And you want more character - the entire reason for going through the trouble.
Are you arguing for or against cool temps? And cooler temps mean a more complex flavor, as it gives all the organisms time to reproduce and do their work. Elevated temps favor bacteria over yeast, so youll get more acidity and less funky/esters at higher temps.
Third - the acidity does not come from acid in the fruit, it comes from lactic acid producing bacteria that consume the fruit (and acetic acid from oxidation from long fermentations). Optimal timing of the fruit addition has not been established by anyone.
Actually this really isnt all that true. Adding a high acid fruit to a beer can make is slightly sour. Adding high acid fruit to a beer thats already sour and it can become overwhelming. How do I know? Ive done this in the past. You cant ignore acid thats in the fruit, I think beers that get fruit should have a softer acid character to begin with
As for fruit additions, I dont think you can say that no one knows when is best. Adding fruit very early and the flavor will diminish considerably. Adding it late is best to preserve the fruit flavor in the beer. If you taste a fresh young fruit lambic it generally has a large fruit bouquet, if you age that same bottle 6mos to a year the flavor has dissipated dramatically, and the bretty/lambic flavors dominate
So like I said, everything goes out the window. (i.e. you use aged, oxidized hops, you infect the beer with bacteria, etc) Do your own thing and see what happens.
Not really true when adding a culture from WY/WL. There arent too many large differences to expect from these blends. The nuances maybe different but in general they all have very similar flavors, and unless you are doing something terribly wrong (tons of 02 etc) it will be tough to produce something terrible
As for aged hops, this isnt necessary with blends, as you dont need the antibacterial protection when your adding a known quantity
This all goes out the window with spontaneous fermentations