The main blocker on using pixels has been getting them from the emulator. I doubt pixels would give a big advantage over RAM features, especially after projectile and stage info is added (there's a PR pending). Captain Falcon (the main character used) doesn't have projectiles anyways.

In fact, RAM features are likely to be much more useful for model-based approaches, which may be important for solving the action-delay problems.

As for multiple characters, the character ID is available to the network. I doubt pixels will be help there either.