In simple terms, the finings attract the proteins and yeast by having a positive charge to their negative charge. Depending on the yeast, the negative charge could be more or less. I am not aware of any research that shows how well finings will work on different yeast strains (which is more about the amount of fining material you need to add).
The fining sediment has a different makeup than the simple yeast flocculation. If you don't rack off the sediment before bottling, you will end up with a mix of volatile fining sediment and more tightly coupled yeast sediment. The fining sediment tends to stir up into the beer much more easily so when Weego fetches a beer from the fridge, there will be a lot more gunk floating around in the beer (look, I eventually got to the simple answer).
As for cleaning, I have no idea.