Harrison Ford may have finished up his run as Han Solo, but he did have some input on Solo, in the form of insight on the character.
“What [Ford] did so beautifully for Alden was he talked a lot about what he remembered when he first read Star Wars, and what George had done with Han. Who the character was and the conversations he had for so many years with George about how that character developed,” [Kathleen] Kennedy says. “He gave Alden that kind of insight which was invaluable. There were several times in the course of making the movie where Alden would actually recount some of the things that Harrison had pointed out. I think that was really, really helpful to him.”
We also get confirmation that Solo is keeping Han’s backstory as an orphan, and how that played into his bond with Rey in The Force Awakens.