Hi
1) The law does not differentiate between a registered WILL or an unregistered WILL as there is no legal necessity for the WILL to be registered.
2) Since your father has left behind a WILL, you can get the WILL probated/Letters of administration issued by the court and once the WILL is probated then the properties are distributed in accordance to the WILL.
3) For probate the process time lines will be approximately 6 months.
4) Court fees for probate/ letters of administration will be 5% of the market value of immovable properties. Since you have paid the court fees at the time of probate application, no further stamp duty is required to be paid at Sub-Registrar office for transfer of property. Registration fees at Sub-Registrar office should still be paid.
5) Court fees payable at the time of probate/letter of administration application will be 5% of average 12 months price of stocks if stocks are involved. No further fees is payable for transfer of shares
6) In general Family Settlement deed or Partition deed are executed if and only if the father has not left behind a Will
OR
7) If the WILL does not cover certain properties, then Family settlement deed or partition deed is executed at Sub-Registrar office, jointly by all members. The fees for family settlement deed / Partition deed is about 2% of fair market value of property.
8) Since most of you are abroad, you can sign the copies of family settlement and get your signatures attested in respective indian embassies.and your mother can then register the family settlement deed for and on behalf of you( subject to you granting power of attorney to her for registration of family settlement deed/ partition deed).
Hope this information is useful.