Is it permissible to eat from a vow designated for the poor and needy, and is it permissible for someone who helps in the distribution to eat from it, knowing that the vow is "2 sheep, cooked, to be distributed among the poor and needy," and it will be fulfilled after the first salary from the vowed job?

It is not permissible to eat from this vow or to feed friends from it, unless they are poor, because you have designated it for the poor and the needy, so it is not permissible to spend it on others. Furthermore, the person who makes a vow conditioned on something happening is not permitted to eat from it.