Hi, I am also related to Judith Riguad thru her grandfather Abraham Dugas.
I was wondering where you found the info that Judith was related to the house of Rohan? If you have a reliable source for that, it may clear this up.
There is some confusion as to who Abraham Dugas' father was. Some trees on Ancestry list Abraham's father as Pierre, but the dates don't make sense. Pierre died in 1596 and Abraham was born in 1600... It makes more sense that Nicholas was the father of Abraham, but I don't know how to double-check the sources. I don't know which version is correct because most trees don't have any sources sited. I'm afraid that it may be a snowball effect of incorrect data.