What is the ruling on partnering with a bank employee to acquire the money of a deceased person who has no heirs, and is it permissible to partner with a non-Muslim in international trade?

You do not have the right to take the money of someone who died without an heir, because their money returns to the public treasury (Bayt al-Mal) to be spent on the general welfare of Muslims if the deceased was Muslim, or to the people of their own faith if they were not Muslim. As for engaging in business partnerships with non-Muslims, there is no religious prohibition against it, provided that Islamic financial regulations are observed. However, it is preferable to partner with a committed Muslim.