Did I miss how much money you have saved for DP/investing? Because you seem like you're pretty darn financially stressed to pull this off at all, even if you stay in your house. If you're sitting on a pile of investments and savings, different story.
As I see it:
-Current income ~$40k (?) or $3400/mo. I assume this is after taxes.
-Current expenses $1271/mo with nothing for home maintenance, car maintenance/licensing/registrations, internet/phone services, emergencies, etc, etc. It doesn't look like you actually know what you're spending all that well, since you only used a few categories and round numbers. It would be a good idea to track your spending and see what all of it really adds up to.
So if we're being really optimistic, you have $1500/mo of wiggle room. A mortgage on any of the houses you're proposing will eat most of that (or all) immediately, and you'll be losing a significant amount of your income at the same time? Sounds like a recipe for disaster to me - unless, as I said, you're sitting on a huge pile of money you can use to buy the house.
So, erm, option 1.
-W