What permits are needed to finish construction?

[William Huston]

Hello All, 

I am just trying to make understanding of a property one of my realtor friends made aware to me prior to it hitting the market for sale. I have a couple who started to build a home on a property, but midway they fell into financial issues i was told and the house went unfinished on the property sitting for multiple years in a "dried in" stage. Basically, it only has exterior walls, some stud interior walls, windows and doors, and finished roof. Due to funding, he is needing to sell the property in an unfinished state. 

I am trying to do my research on the property because it's in an area i would decide to move to if i was to purchase and complete the house over staying where i am at now. My question is what type of things do i need to do to assure the house is legal to be completed after purchase. 

I was told he would supply a complete set of building schematics and stated its fully permitted, but when i search the county records I'm only finding the following under the address of the property lot. 

"RES - New Single Family Detached Home Const of Frame Exterior Walls Only"