I just absolutely love that KC set up Saul and Michael's skills with video games much earlier in the series. Saul referencing playing Xbox with Angel and his "Gameboy thing" while out with Burt and then later offers the same device while staking out the farm with Victor.
Meanwhile, Michael has been shown playing a game exactly once, when with Puck waiting for a call on the SAT phone. Michael needed Puck to help him past a difficult part and it was implied, if not outright stated, that Puck often had to help Michael when playing video games. Thus why Saul can work KODI and Michael has trouble. I laughed out loud on the treadmill when I put it all together. Plus Saul referencing Halo, as a Halo fan I appreciated that. It does help keep it secure that KC has been telling us the truth and had everything more or less planned out all along.

As for Scratch's return, about damn time! Funny how CJ's defenses would have held off even the likes of the Behemoths or the Inklings for enough time to mount a counterattack or an escape. When CJ earlier stated all she had set up, I thought it was nigh impregnable. Then a swift human assault with explosives makes them helpless in seconds. It kind of fits back in with Tanya's supposition that the zombies have only become so fierce some and advanced due to the pressures our mains have given them. Who really is the greatest threat? Ink wants his new species to survive, and part of that surviving does involve eating people. Scratch wants pain, weeping, bitter gnashing of teeth...when she can correctly articulate her goals.