Assuming you are talking about a spec home build and sale scenario, this is my understanding:
1. Yes, that would still be excluded. A lot isn't a "dwelling" under HMDA, so the purchase of it is irrelevant. For HMDA purposes, the funds are to construct the home for sale.
2. If I am following you correctly, a borrower gets a loan to both pay off credit cards and build a house for sale. You would have to determine whether the loan is primarily for a business purpose (if credit cards were consumer), if so, then I do think it would be excluded. Similar to the lot purchase, the payoff of credit cards is excluded because you have a business purpose "Other." For HMDA purposes, you are looking at the rest of the funds to build the dwelling for sale.
3. That is how I understand it, yes. Kind of a unique scenario that the CFPB probably didn't envision to do otherwise. Creditors usually would not mix doing a construction loan that had a draw schedule and inspections, etc. with funds used to do other things like payoff credit cards. It would mess with the LTV calculations and giving draws for work performed.
4. As Dan noted, yeah, person here can be a business entity.