We, and the people I know, don’t sell the whole house. We sell certain cabinets, closets etc. These are listed in the sale contract and we label each cabinet “chometz, sold.” Everything else belongs to us and we use. And many people I know do not sell anything at all, instead they carefully get rid of every bit of chometz. As far as I know, it would be very problematic to live in the house and use your clothing, Pesach dishes/pots, etc, if you sold it. Please speak to the real Rav of your shul- who you will use to sell your chometz – and clarify this point with him.
By the way, LB, I think going up to a stranger in the supermarket to ask halachic shaalos is even worse than asking CR people- at least here you can form some opinion of how the person thinks, what he/she believes based on how he/she posts. How do you know that he really was who he says he was, and that he was giving you a serious answer?
Personally, if some stranger came up to me and blurted out what seemed to be a random question 2 days before Purim, I would think he was joking and maybe would respond in kind.