Ok, think finally something went "click" upstairs and I'm understanding the diagrams. (That only took 3 days
.. I ... never ..... . said...... I ...... was............ swift ..........
)
Do the seaswirls run off the water pressure or do they have an independent motor? I can't remember.
I don't -think- you need a pressure rated pump for this, but I'm guessing you do probably want at least a Little Giant 4 or Mak4 for this, given the multiple outputs.
BTW, Muck has a good suggestion of going with a separate closed loop if the goal is to remove the need for powerheads. I find that there can be an upper threshold with flow through a sump (before you start to get microbubbles), but with an independent closed loop you can increase flow beyond that without having to worry about touching the sump return. The only real drawback (I think) about closed-loops is that pumps tend to use a lot more energy than powerheads.