I (a male) have been invited to volunteer teach in Indonesia for two weeks in December. I have been invited by a (female) friend. I said I would stay in a hotel. She said in her culture it is rude to rebuff an offer of accommodation. She has offered for me to live in her house for two weeks, with her family. I would be in my own room, or sharing room with her brothers. I would not be sleeping in the same room, let alone bed as her. As mentioned, her family would also be in the house at the same time (siblings, parents and cousins for Christmas celebration). Is this cohabitation?
No. From what you described, it looks like you would be a guest in your friend’s home, along with her family. I commend you for your conscientious approach to this situation.