I have an XP 2. I use polyester fiberfill in addition to the 2 grades of black filtration foam.
The charcoal will neutralize meds or chemicals if needed, but not really needed for filtration if you have the sponges and floss. It needs changed frequently and I don't use it, nor the zeolite. If you have a properly cycled tank, you don't need the ammonia control.
In the 2 baskets I have on the XP 2, I have 2 coarse foam pads and 1 fine one on the bottom with a little fiberfill, and in the second I have biostars and fiberfill, and then I top off with the second finer foam sponge to be sure none of the fiberfill goes up in the inpeller. the white filter pad wore out early and I didn't replace, just rely in the fiberfill for fine filtration. It even pulled the brown color out of the water I had from my driftwood.
I use plain craft fiberfill in the bag from Walmart. Cheaper than buying from fish stores. I just toss it when I clean my filter, but rinse the sponges in treated water and reuse.
When I set up my new 75, I plan to get an xp3, and plan to arrange in a similar manner. I did get some ceramic rings, and will split these up between both filters, and split the biostars between both too.