I'm not seeing Han Solo in Alden Ehrenreich's performance so far or even in his look. I'm hoping I'm wrong and he blows it out of the water, but yeeeesh.
On the other hand, I think they nailed Lando's look with Donald Glover.
Interestingly, I came across this actor,Anthony Ingruber, who wanted the role and man he looks a lot like a young Harrison Ford. But I heard his acting chops weren't up to snuff.
Here's a youtube video of him doing a Harrison Ford impression.
https://www.youtube.com/watch?v=bba_wPdLxp4
