1) Whether my buas can gift this small eastern portion to us without taking consent from their childrens or husband
Once your grandfather has gifted the property to both of our paternal aunts, they after inheriting the same have become the absolute owners of the house. This means they do not have to take consent or permission from their children or husband to gift or transfer any portion or entire property to the person of their choice.
Therefore the consent of their children or husband is not necessary if they are willing to gift this portion of property to your mother.
2) Whether their childrens have any right over their mother's property(STRI DHAN)?
NO
3) If we agree to take gift then do we need to take signature from all of these childrens & of my uncle on this "Registered deed of Gift"?
No, their signature is not necessary and they cannot legally dispute this transfer anytime even in future.
4) Will Registerd gift deed is a solid document or a sale deed?
Kindly advice a fool proof legal solution what to do ? We don't want any problem in future if the sons & daughter dont sign on the deed. Kindly specify there role of challenging gift
Registered gift deed or a registered sale deed in your mother's favor is a valid document which cannot be disputed or challenged by anyone including their children or husbands not only now but anytime in the future too.
The children of your paternal aunts or their husbands do not have any rights or share in the properties that belong to your aunts hence any legal action by any of them in this regard are a mere waste exercise and not maintainable in law.
5) Can this gift be challenged in court?
Even if it is challenged, it is not maintainable or tenable in law.