I think I've eventually arrived at "Everything is an illusion but it's the only illusion we have, so it's as real as anything else." Everything we experience is a subjective response to a stimuli and no two people have that exact same response. It's irrelevant whether we're meat golems piloted by ghosts, dream figments, or NPCs in a massive simulation, because we live in a world with billions of others, and what we do matters to ourselves and those others.
I guess recognizing everyone else as real puts me in the Everything Is Real camp.