I do have a very close friend, Hongkonger. He owns two flats in Hung Hom. One of them is now residents-free. We discussed that it is possible if me and my wife could live there for free and he agreed even to sign a rent-free contract. It is the way we need since we have only 70 000 HKD per year, so free rent could be solution.
Therefore:
it is possible to sign a contract for rent with monthy payment of zero or something like that? OR as alternativem can the owner write a letter that he lets me to live there for free (like support letter from family)? but will immigration accept such a thing if owner is not my relative? how to convince immigration that it is my good friend and not fake for visa app?