Ownership transfer based on registered will

My father left a registered will with clear instructions on succession of various assets. Am trying to understand applicability of probating the will/legal heir certificate/succession certificate for diff assets. Pls. advise, what is required for (Hindu law is applicable) : 1.Transfer of car registration to mother's name 2.In future if we have to sell the flat (co-owned by my mother) 3.Liquidating other investments like mutual funds, bank accounts etc, where nominees are clearly mentioned (either my mother and/or sister)