Gear arrangement and what to do once you catch a fish

To maximize the quality of my fish, as soon as I catch a fish which I'm going to keep, I put it onto a stringer, bleed it for a couple of minutes, and put it on ice in a cooler.  If you leave fish in your rear cargo area, its quality will degrade quickly.  I've tried various softsided coolers, but prefer to strap a hardsided cooler in the rear cargo area of my Revolution.  A hardsided cooler holds a lot of fish and ice, it's easy to load fish into, and it's easy to clean out at the end of the trip.

When you put fish and ice into a cooler, the ice will quickly migrate to the bottom of the cooler, leaving the fish exposed to warmer conditions.  I put at least half of my ice in a mesh bag.  After I drop a fish into my cooler, I pick up the mesh bag and plop it down on top of the fish.

Aside from safety gear, less is better on a kayak, especially when starting.

Presuming you have the tankwell version of the Scupper Pro, I would keep a game clip on a tether behind me, clip fish to that and then toss them in the tankwell. If you are going to be out for a long time you could get an insulated kill bag. You can straddle the kayak with both legs in the water for extra stability, and sit side-saddle when accessing things behind you. If you aren't comfortable doing this, practice until you are. A lot of people also leash their paddle (it's not an oar!  ) so they don't have to worry about losing it.

Yes I would always lift my rear with both hands an swing both legs over the side into the water when I wanted to do anything behind my seat. I tied my game clip to the kayak behind my seat. Not too much rope, but enough so you can bring it forward enough to comfortably add more fish. I'd pull the rope when I wanted to add more fish and I hold the end of it and swing it and kind of toss it into the tankwell to put it away.  Practice makes for comfort.