I would be weirded out if Diego Luna showed up in the Han Solo film since the film is supposed to take place from when Han is 18 to 24 and Cassian is around 4 years younger than him, meaning Cassian can be, at most, 20 in the film.
honestly nonny, the diego luna binary (beard:no beard) almost assures that if diego were to shave, he would look 20 years old again. however, it appears that the “diego luna” spotted on set looks nothing like diego luna at all, so bad reporting all around.
I’m just generally wary of new content for the r1 characters at this point. on the one hand, I want more backstory for cassian but on the other hand, who knows what they’ll do? it’s unlikely they would try to make him more palatable to readers as male characters are allowed to have unsocial traits, but it is possible they might try to make him more “rakish” to fit in with the new han solo branding.