The current line of succession, by Monaco's revised Constitution of 2002, includes only the legitimate descendants of Ranier and Grace. It currently excludes Antoinette and her family members anyway.
I'm guessing that the next possible line of succession could perhaps come from the descendants of Prince Honore III (1720 - 1795) found here:
Descendants of Prince Honoré III of Monaco
Of couse the constitution would have to be revised yet again to include these possible heirs.
Feel free to correct me.
