Sump designs and operation

In picture 2, where the 2" baffle width is, there is either filter media or a bubble sponge there(raised by egg crate and pvc), on the right is the skimmer and on the left is return

In picture 3, on the right a skimmer, on the left a refugium, in the middle the return pump.

In picture 1, on the right filter media(raised by egg crate and pvc), on the left the return pump, in the middle the skimmer.

In picture 1.5, on the right filter media(raised by egg crate and pvc) and the skimmer (divided by 1 baffle), on the left the return pump (this is kind of a step up from 1 because it has a bubble trap, 3 baffles, instead of 2 and gets rid of one of the baffles on the right. Thats why its 1.5, because its similar to 1.

Thanks everyone and please, please post what you voted for and exactly why. Keep in mind each tile is 1 square inch and all of these tanks are 8" in width. These are all sketches and i could eliminate all but one right now but i have too much questions about all of them, which are too complicated to show through computer, so for now i just wanna know which one you picked and why you picked it. Thanks again.

Instead of me asking what functional problems they could have because its too complicated (not in person), maybe you guys can point out what can go wrong with each or what problems you spot? Thanks a lot