Does that skimmer pump inject the air or does the air get injected later? For example mine has an air inlet at the pump intake so that the air is injected at the impeller which makes for a mass of tiny air bubbles. But some use high quality air stones to inject the air. If you decide to do it the first way you don't need an air pump or lines... just a short piece... .
I'd think any magnetic coupled pump with similar GPM and head rating would work. You may need to rig up an air line to where the end of it is somewhat inside the inlet to the pump, then mount the other end of the air line a fair amount above the water high line with an air valve on it so you can adjust the air injection and thus the water line, ....which will be adjusted to be up on the main vortech barrel below the catch bowl somewhere. That will be where the bubbly water stops and the foam starts. On mine it is about 1/3 up the barrel. It needs to be so that protein is captured but not high enough so the catch bowl is loaded with foam. Looking at the picture I have no idea where that would be... with this being a custom job, you may have to play around and see. My wild guess ...it may be just under where it gets small....or there abouts.
Since it is so much to figrue out,,,..... I think you need to just ship the whole thing to my house... NICE rig. Test that stand... make sure it is stout!
