I am thinking of buying a house and as a first home buyer I would be living in it. The first question is, if I get some flatmates in would I be able to deduct my interest payments from my taxes as an expense?

Secondly, supposing I believed that property prices were about to fall off a cliff and bought a put option against the likes of FBU or some other listed property investments as a hedging arrangement, would I be able to claim deductions off that?