I think so. At the end, Shulk and the rest are on land that previously didn't exist, implying that he remade the universe into a place where it was more than just the Bionis and the Mechonis. My guess is that they need to leave their new Earth after going through all its resources and have to find a new planet. Or they could be on the same planet and Shulk only remade that planet, meaning other humans existed far away into space, escaping Klaus' experiment. There's a whole lot up in the air and I love it.
Pretty sure they plan on topping it with new races, a bigger world, giant robots, flying giant robots, space... I'm down for it all. There's a chance of Shulk possibly being it because, well, becoming a god (even if he denied it) could have provided him some sort of longevity. But it's a stretch.
I think the spirit bosses were Alvis' influence, reminding Shulk of where he's been and what he's done to get to this point while simultaneously testing him one last time to see if he was ready.
I love the ending music too
I need to watch that trailer again too.