The daughter would not have any share as her father passed away before 2005, therefore stepson has no share in the property as per Hindu Succession act 2005 amendment.
The two sons would have equal share in the property and since they have passed away there share would be divided between the legal Heirs.
Your cousin would have half share in the entire property and the other half would be divided between you and your sister.
Feel free to call.
Regards.