Read that they found unused scenes from Episode IV that they spliced into Rogue One. Basically, the fighter pilot cockpit scenes were shot in 1977 (or whenever Lucas filmed them). So that is why you can see the original Red Leader (non-CGI) fighting in the climax of the movie. How freaking cool is that? I understand the Tarkin CGI, but this is a universe where they communicate via hologram. Why couldn't they just have the Director bicker with Tarkin's hologram for most of the movie and then have his CGI character show up at the end, if necessary?
I was referring to the second CGI character that you had a problem with. My wife thought that it was old footage. I didn't know about the cockpit scenes being reused. Pretty cool.