With an Active Forums license, you get access to the script that migrates DNN Forum to Active Forums. When you look at the detail in that script, there's obviously something missing from the scripts posted in this thread, for a reverse migration. The author of the scripts posted here mentioned they were only meant as a starting point, not a complete solution, and that is apparent when you compare these scripts to the ones for DNN Forum to Active Forums migration.
But I had hope, and tried to use the scripts in a test environment. When executed, the post message Body wasn't migrating, and User Post counts weren't updating. Beyond that, I didn't check integrity, but it didn't 'feel' like it was a strong migration, so I stopped trying. I don't code, so extending the scripts provided in this thread isn't an option for me.
But I wish someone would build scripts as good as the DNN Forum to Active Forums script written by a coder from R2Integrated, formally Bi4ce. A well-engineered Active Forums to DNN Forum migration script would be an asset to the DNN Forum project.