I don't think there are sources for the Dagobert-23 connection. According to our consensus, it should be removed with a note in the bios. As for the LNAB, I'm out of my depth, but I would suggest finding either a conventional way to talk about this line or finding the first ancestor and using that ancestors name as the LNAB. Sorry not to be more helpful!
In fact, "David" might be the best choice.