Looks like more of a family dispute.
Fatima Bhutto was even at war with Benazir.
I don't know how much political influence does Ghinwa have, may be confined to some nooks and corners of Garhi Khuda Bakhsh.
Sassi Bhutto is an unknown political entity in Pakistan.
The article does hinted that Sassi might be here to grab her share of the property and to help Ghinwa and family out.
Bhutto family has 8 young cousins and there might be a dispute brewing up as Zardari is holding up all the property uptil now for his 3.