Here's my set of theories on why Ingruber isn't on the list:
1. It's a bulls*** list that someone at Variety made up or is like the old rumors that Kenneth Branagh was going to play Obi-Wan in the prequels. It's idle speculation and total nonsense.
2. Ingruber doesn't want to do it. Either because he has no interest in the part, or because his agent said "Anthony! You can't spend your entire career playing nothing but Harrison Ford parts!"
3. Ingruber is already committed to something else and is conflicted out of the project.
4. The people running casting at LFL are morons.
Of the possibilities, I'd say #4 is definitely not the case. They cast TFA exceptionally well. I find it hard to believe they'd blow it with the first non-episode film, since the non-episode films are likely to show up much more often.
#1 is probably the most likely, but #2 or #3 are also possibilities. Much as I think he'd totally nail the part, there's a real risk for an actor following up one gig with a nearly identical gig. He could end up totally pigeon-holed, and "Plays younger version of Harrison Ford" is a pretty narrow niche.
That said, I watched a video of Ford and Ingruber talking about working together on Age of Adeline. Ford started the video, and I switched to another screen while the audio played in the background. At one point, Anthony Ingruber started talking and I had no idea that it wasn't Ford anymore. He was just talking like a regular guy (not in character), and it sounded exactly like Ford. It was uncanny.