Agar property grand father can naam hai to fuwaa ka sign nahe chyia grand father will or gift sa sari property son ya grand sons ko de skta hai .

If it is self acquired property of your grand father he can execute will bequeathing property to grand  children 

2)signature of uncle is not necessary 

3) in alternative he can execute gift deed of property during his lifetime in favour of grand children 

No such requirement is there. Your grandfather can give his property to anyone according to his choice.

If the said property is grandfather's self acquired property then he doesn't require any other person signature. 

Nahi,

ग्रैंड फादर की स्व अर्जित प्रॉपर्टी में किसी का कोई हिस्सा नहीं है एवं ग्रैंड फादर अपनी संपत्ति किसी को भी दे सकते है और बेदखल कर सकते है I

किसी के साइन की जरुरत नहीं है सिवाए ग्रैंड फादर के, या तो वसीयत या गिफ्ट डीड I

agar property aapke grand father ki ho to kisi ki signature ki zarurat nahi hai. 

If it is your grandfather's own and absolute property then he need not obtain permission or consent from anyone to transfer his property to anyone's name by any mode or in any manner to whom ever he may desire.

However if your grandfather is insisting that she may have to give her consent, then it would be better that let him obtain the same so that she will not dispute the same after the lifetime of your grandfather through court.

Dear 

Apke grandfather ko apni property apke naam pr transfer krne k liye apki Fuwa kaa sign nhi chahiye lekin agr us property me Fuwa kaa hissa h to us case me Fuwa k signatures chahiye honge.