I'm told the screening criteria credit score is on the higher end .But most of the listings I see are also on the same league.

I'd be happy to meet you over there and give you my opinion if the foundation work and remodeling is worth the expense.

If the figure of $1200 is being floated on the listing it’s highly possible the current owner is locked in and grandfathered at this price and even if you get a policy with the same insurance company your policy will be significantly more expensive.

(Fuzzy math--would need to see the details, all the other disclaimers...)You can use a rental agreement to offset the payment of the home you are departing for underwriting purposes on the new purchase loan. 

Would confirm to the rest of the sfr in the neighborhood?

Contact the zoning department and see if you can get the property rezoned as a duplex.

Building a separate one isnt cheap , I have run the numbers , with permits , nd the other county BS its close to $200K for an 800 sq ft building . 

That's a wild story in the mobile home investing niche.

Not the cheapest 25% or the most expensive 25% but I’m the middle, where people want to and can afford to live. 

Once the HELOC is in place, your father-in-law could loan you the funds to invest in real estate.