I would like to put two offers in at the same time for the seller to choose one for $225k using FHA loan and another for $250k with $175k as bank loan and the seller caring $75k has a second mortgage with 60 installments of $625 zero percent and ballon of  $37,500 at the end of the 5 years. 

If you put a plan together, you will see that your second paragraph is all over the place with ideas... this is actually very dangerous in a business setting.  

Then the warranty company insisted on getting a second opinion.

I currently own a duplex in NJ, I live in one apartment and rent the second one.

I wanted to jump in for a quick second and introduce myself.

Second-to go along with that,  I would triple check your landlord laws and/or speak to an attorney before you, yourself, enter the apartment without the tenant there.

The second floor has 3 bedrooms and should rent for $1,200. 

Second, the cost of materials is soaring, but hasn't yet stopped the demand for a new home on the buyer's side.I know for certain that some banks are flipping houses now, rather than sell off their REO properties for discount.  

A second for new flooring...luxury vinyl planks. 

My analysis is similar to what @Dan Heuschele          FYI: I went to The City of Vista meeting two weeks ago and they are considering reducing permit fees on Granny and Second Unit (Granny with Kitchen).