Yeah, if Chandragupta/Chanakya were behind Dhananand's death, it's unbelievable that Durdhara would marry either of them. I thought she was a different princess.
In this story, once she finds out that CGM is her father's enemy, they'd become enemies. Also, if CGM kills her father to avenge his mother's death, it's unfathomable that she'd marry him. Some historians may have made this up to give CGM some legitimacy as a member of a royal family - something not really needed, since every dynasty @ some point had some founder or the other.
Also, was there any woman who did what they are depicting Durdhara as doing, or is this complete fiction and an attempt to make Durdhara as flamboyant as CGM? They'd have done better trying that w/ Cornelio.