Tough subject. We have had this discussion on this forum a few times with mixed results. Basically you are talking about a strategic default. You will renege on a signed, pledged agreement.
Corporations do this all the time without any feeling of guilt at all. They claim it as part of doing business. The public seems to accept this and continues to do business with corps that default.
However, in the past, personal default has not been looked on quite so favorably. Some see it as not following through with your promises and then you will never be trustworthy. You are only as good as your word.
I, personally, rely on my tenants to keep their word that they will pay their bills each month as agreed to. I never do business again with one that doesn't honor their word.
However, I do see a lot of families upside down on their mortgages, maybe for life. They would have definitely taken the profits if the appreciation continued but don't want to take the losses.
Bottom line is, to me, it's a personal decision. I don't think it's right to come here and expect to get permission to default on an agreement. However, I do understand if you have to. But business, as we know it, is based on trust and honoring one's word.
My vote is #3 and hit your business ideas hard and heavy.
Good luck with your decision.