“It’s too late to replace him on the ballot.”
It’s never too late.
You can run an organized write-in campaign, but to win, you need to do the Lisa Murkowski thing and have name recognition and an organization and months of prep time and all that. And if that happened, the Repubs would get behind Luther Strange anyway.
Absentee ballots are already in the mail here.
I’m an attorney and tend to know a lot of this esoteric nonsense, but what happens if Moore wins and the Senate refuses to seat him? Does the Governor appoint a replacement again? Are we in an endless feedback loop?