Is the education I will receive in a private school, funded by building a wedding hall that contains musical instruments, unlawful (haram)? And will my future work resulting from this education be unlawful (haram)?

This question stems from intrusive thoughts (waswas), so you must ignore them. It is not forbidden for you to benefit from what your father spends on your education, and the permissibility of his money is not affected by him renting out a wedding hall to those who use it with musical instruments. Mixed money is not forbidden to deal with. Even if the education were funded by unlawful money, it does not necessitate the prohibition of benefiting from the certificate and working with it.