Ahhh Gamakuma, Inukuma, and I GUESS HARIME.

Have you looked into cerealia at all? We've got a me and a Ryuko for castmates at the moment. It's about medium pacing, aside from some events that get pretty big. But it's a mixed of SoL with plot stuff too. There's mild horror stuff, like in our last event but it's almost always skippable, and never really that hardcore.

For the Mutt especially, it's all computer-based, and he'd have a ton of opportunities to get involved with plot.