What is your process for animating multiple characters interacting together in a scene?

I've rigged up a few animations using just 1 character each, but now I'm working on a personal project that involves lots of different characters. They're all rigged and ready to go. I have the first 2 minutes finished but it was a mess trying to come up with an efficient workflow.

The scene has 4 characters interacting together. They are smart objects in Photoshop, but otherwise 900x1000 pixels in size. Yet the program started crashing and freezing almost once an hour around the 1:30 minute mark.

I figured maybe there were too many characters on the scene, so I tried splitting them up into individual scenes, one per character. That in itself was a mess because you can't copy audio over from the timeline, but whatever, I can work around that. The biggest issues were that 1) it took forever to switch from scene to scene (not terribly long, but the program definitely hangs when you're trying to open another scene; there doesn't seem to be a way to cache them or keep them in tabs along the top for quick loading?), and 2) scene-in-a-scene is a little useless because I can't transform the x/y coordinates of the scene...? I put it in and there's no further editing to it? Like moving one scene next to another scene so the characters are actually talking to each other?

I'm also using After Effects, and have totally given up on the dynamic linking if I wanted to actually get any work done. So slow.

It just feels really hard to make this cartoon with multiple characters interacting with each other, and I'm wondering if someone has better ideas?