That is a lot of questions Mr.Shnatter, this is what I have to say for now:
Simon Mao is the chief fellow at Convoy. For further details concerning his commercial relationship with 3rd parties, you can ask him.
S2 and S2+ are slightly different flashlights. The S2 is a less popular model as far as I know. Sold in gray and black, it has a shorter pill and a deeper reflector, this means it should be more throwy. But I can't make a direct comparison, so take this with a grain of salt (wait for others' reports).
If you buy from the Convoy flashlight store in AliExpress, you will be dealing with him directly. You won't straight find the best prices there, but as I say above you can get a discount.
If you are looking for sales of Convoy flashlights, you will have a better chance taking a look at 3rd party sellers. Here is a link to the current last page (#74) of the official Convoy thread, just in case you want to ask something there.
The above behaviour is caused by the (SST40) driver's temperature control feature. If you get an S2+ with such driver, it will behave exactly like that, if only it will step down a little bit lower due to the overall lesser mass and size of an S2+ versus an S21A.
You like “cool white”? Well, that's ;-) noobie. And while I can enjoy pretty much all CCTs, I prefer to stay in the lower CCT kelvin range. It is best suited for night time, “warm whites” allow you to adapt to night vision conditions much better, and overall look better anyway imho. 