Is it permissible for a pilgrim to enter the free Hajj camps designated for employees of specific entities through personal connections, and is their Hajj valid in this case?

There is no harm in a person asking for a tent to stay in Mina, because he has the right to reside in it. As for food, drink, electricity, and the like, there is no harm in using them if the official in charge of the camps permits it; otherwise, it is not permissible to benefit from them. Usually, the official allows the use of these things, and they are considered a form of hospitality. In this case, all of that is permissible as long as permission has been granted by the official.