As i know non muslims(hindu) are kafir n therfore food made by them is najis so it is not allowed to eat but can we eat from a restaurant in india where by common sense i can say workers(chef,cook,waiter,manager,staff)in it will be hindu?

2.can we eat from a restaurant in india where owner and name of restaurant is seen to be muslim without using common sense that most of the workers or some of them will be non muslim or here also we must see all workers are muslim.

3.can we eat food in a restaurant chain like mcdonalds,kfc,cafe coffe day where food is produced by machines but then too we can say in many ways non muslims are involved in it ?

1) yes Hindus are Najis as per the ruling of Aagha e Seestani if it is touched by kafir with wet hand then it is pak but In above situation it is hard to say that it would not be touched so consider as Najis. Because Chef, waiter all are Hindu that means there is not any possibility of the taharat .
2) If restaurant own by Muslim in front people are Muslim then do not investigate it is palak.
3) Mentioned chains are helping Israel so refrain from then it will be help to oppressor. If it is known that workers are non Muslims then off course then not allowed to eat in the light of the answer of the first question