You can't find Rehat Maryada in any Gurbani Granth. It is a collection of codes of conducts written by contemporary Sikhs of the times of Guru Gobind Singh - but it does include Gurbani to refer to how we should live & conduct ourselves.

The best thing to do is consult the Panj Pyaareh and the next Amrit ceremony. Go prepared to take Amrit and consult them before the ceremony starts telling them your situation. Whatever answer they give will be the best solution for you.

As the samosas were fried, the oil has gone into the pastry, and meat as well, which you still put in your mouth. Mistakes do happen, however you would need to go pesh at the next Amrit sanchaar and seek guidance from the Panj Pyaarey. They will be the best ones to advise you.