Im not worried about the electrical work.

New roof, possibly some settling issues, probably missing some plumbing and/or electrical, definitely will need sheetrock/mud/paint/carpet work.

I always tell this story to new tenants to stress the importance of water damage and insurance.On a side note, I also make sure on electrical outlets that the wires are wrapped around the terminal and screwed down kung fu tight.

You need to keep in mind in most cities when you start rehabbing that means getting inspections and many times they will want a total upgrade of the electrical and plumbing. 

Water is free, and free electricity/gas for up to $120 for the whole house.

I prefer my unknowns to be related to the house: plumbing, electric, layout problems, mold.

They come precharged all you need is to hook up the electric, the copper lines and pull a vacuum.  

I agree.After inspection he wants to max out his seller’s assist, and perform some costly repairs (upgrading the old ungrounded electrical).

@Michael GessnerI'll look into joint compound; and all work, drywall /electrical, was thru professionals.   

The main floor did not need any permits since no walls were added, and everything was cosmetic, but the basement has new walls, electrical, and the bathroom was existing but moved to another location.