1.The jointly acquired properties were declared in the will as Self-acquired by my father. The will saying contradictory CAN BE CONTESTED?
The jointly acquired properties shall have names of the all the purchasers in the registered sale deed document and not one individual name alone. If the property was purchased on any single individual name alone, then that individual alone is the sole owner of the property. The claim for joint ownership cannot be maintainable even if contested with documents for funding the purchase because the funder is eligible for a share in the property as a joint owner and registration to have been done accordingly, in your case this is missing.
2.Is there any possibility of getting Injunction Order to stop the transfer the title of the properties as per the WILL in the name of sister & my mother.
since, it is jointly earned properties.
Again, jointly earned properties is nothing but a misconception in the eyes of law. Moreover the will shall come into force only after the demise of testator. There can be mandy will written one by one nullifying the previous ones during the life time of the testator.
You have not stated that whether the will has come into force or not?
3.Equal rights on the property for me and my sister holds at what status, since the WILL IS DATED PRIOR TO THE
ACT. i.e., 2001.
As on date the will has not come into force. The will shall come into force only after the lifetime of the testator. Moreover equal rights or any rights on the property shall be for the intestate properties only and not for the self acquired properties which has been disposed by testamentary disposition.
4.As per my knowledge, the WILL can have the scope of 1/3rd of his total assests. But the WILL covered all the assets. Is the WILL valid?
The will is very much valid because the concept what you refer is for the muslims only, as per the Muslim personal law, a testator can bequeath only 1/3rd of his property. Being a Hindu this law will not be applicable to your case.
5.Actually I have one married son and one married daughter. My sister got one married daughter. My son, as a grandson, can he challenge the remaining jointly acquired property which was assigned to my sister and mother in the WILL?
Any rights for your children in the properties shall be only after you, hence do not mis-read and misunderstand law and bend it to your convenience. Your children can claim any share as a right from your properties alone that too after intestate death and not on your properties which have been disposed by a testamentary disposition.
6.My father is 83 years old. He is earning about 60,000/- (pension, rents, bank intrests). What is my and my childern share on this?
NOTHING. It is his own property, nobody can claim any right in it during his lifetime.
All your further questions shall find answers in the above lines.