Some of these roles may be glorified cameos, rather than ones that truly move the plot forward.
I’d love to see Happy Hogan suiting up with some Stark tech to battle Thanos’ cronies, although perhaps that’s asking too much.
It should be interesting to see how the Russo Brothers manage to feature such a huge cast in Infinity War’s presumably limited runtime.
Smart money says that the battle against Thanos and his forces will be a worldwide event, and we’ll get small glimpses of characters attempting to defend the Earth from their various locations.