Is it permissible to take some subsidized food items from a hotel due to lack of promotion, insufficient salary, and high cost of living? And is it permissible for my brother to marry a Muslim girl in Poland through a group of Muslims and write a legitimate contract to avoid fornication, given the absence of a legitimate marriage officiant and the lengthy official marriage procedures?

It is impermissible to take anything without the permission of its owners. If you are entitled to a promotion or a salary increase, then demand it from the officials.

Regarding the marriage of a Muslim woman in non-Muslim lands, her marriage should be arranged through her Muslim guardian (wali). If there is no wali, then through a Sharia (definition) judge. Otherwise, through Islamic centers, or the woman may appoint a righteous Muslim man as her agent to marry her in the presence of two witnesses. The marriage contract is concluded with offer and acceptance in the presence of two witnesses, even if the official paperwork is not completed.