Erosion filters are very common. The only difference between what you're used to and this one is that the DE is not pumped via a dosing pump, but rather a side stream of the main beer pump is used to agitate the DE and dose your beer stream. Otherwise, same thing. There is still a dosing tank; just not a dosing pump. So to answer your questions:
3)Maybe even easier to clean as there is no second pump.
6)Is Palau west enough for you?
Phillip Kelm--Palau Brewing Company Manager--