1. No your father cannot revoke/cancel a registered settlement deed without a court order.
2.he cannot sell or transfer by way of release, gift or cannot make a WILL against the settlement deed.
3.No, you should not have to hand over the documents.
4. she can file a suit to challenge the deed.you should defend the same.
5.You can pledge,mortgage, or transfer, sell the property of your share as per the deed.
6. Police has no role to decide on a registered settlement deed as it is a pure civil matter, they can take a complaint in file if your sister or father complains about , threat, force, intimidation , fraud to get the documents /deed registered. however since it has been registered , there are many involved in this like registrar and his assistance who done this.The case will not stand on your sister's false complaint.
7.it is better that you should get an injunction refraining your father from alienating/ transferring/selling, gifting your allotted part as per the deed.
8. Approach civil court first with an injunction , then if she troubles you matter is in the court, file police complaint for criminal intimidation. Doing before all these, make use of the property as you wish , pledge or mortgage , your father will not have to sign for the loan.