Are you using an FBV controller with your HD Pod Pro? That's a pretty good solution, one of our guitar players used to have a HD Pod Pro rig, and we tested out the midi control from inside it. I'm pretty sure you can assign the 8 footswitches to be different midi commands per preset on the pod, so there should be a lot of versatility there. Better yet, combining with the SA hub, you can assign the expression control on the FBV to control parameters on an SA pedal, and there are TONS of awesome things you can do with that.
Looks like the RJM mini gizmo works the same as the GCX midi-wise. That is, you send CC values for each loop individually. So loop 1, for example is CC88. You send 127 and the loop comes on, send 0 and the loop goes off. The problem with the POD is that you can only ever program a button to do one thing. So you could program FS1 to turn on your first loop, but that's it. If you wanted to turn that loop back off, you'd have to program another separate footswitch (FS2, for example). I don't think there is a way around that. I'm using a Musicomlab MKIII+ right now, and it has a feature for CC controls that pressing the same footswich again will send the reverse signal (so it works like a stomp box, one footswitch for on/off).
Anyway, if you're looking to be able to turn on multiple loops at one time, I recommend the Patchmate if you're set on using the Pod as your controller. Then you can program, for example loops 1, 2 and 5 to be a specific preset, then you only have to send the corresponding program change for that preset (much like the SA hub).
As for the SA stuff all being in a single loop, that'd be fine (as long as that works in terms of your pedal order - not sure what else you want in your loops). By sending PC's (scenes) to the midi hub, you can bypass each of your SA pedals individually, so you don't need separate loops for them.
Again, if you wanted to get a rig where you could turn a loop in your bypass looper ON while also sending a signal to the SA hub, you could not do that with a single footswitch with the Pod.
Lot of options, depends on your needs. You may eventually want to go with a more advanced external midi controller that can send simultaneous messages to your bypass looper, SA pedals AND your Pod.