If you did any of these things you'd be court-martialed and probably spend a few years in prison because you have violated rule number one.
Independent of the Prime Directive you might want to ask the Ba'ku first if they want your help. Or do you in general force people to do your bidding when you think you know what's best for them?
Actually, the only thing the rules allow you to do is to declare open season on them and allow them to be slaughtered by the S'ona while you sit back and watch. Since they thought they were a pre-warp civilization you're not even allowed to talk to them.
The Prime Directive dictates survival of the fittest no matter how inane the situation, which is why it's a bad rule and doesn't fit the situation in the slightest.