buying a half constructed house

[Nancy Wang]

This is in Dallas, TX area. I am interested in a half constructed house - house was built on top of an existing foundation (pier and beam); The original house was in 1950's and one story, now the owner has framed up 2 stories. The finished items include: brick veneer and siding, frame, exterior wall insulation, windows/exterior doors, electric wires, plumbings, HVAC, bath tubs. 

I have never done any house construction or flipping. I only have experiences in buy and hold. What I can think of the rest of the work for the house is: Sheetrock, paining, flooring, installing cabinets/counter tops in kitchen and bathrooms, tile up around showers, appliances (water heater, dishwasher, range oven, microwave oven), light fixtures, interior doors.

I am posting here to seeking advise on any major to-do items I missed? For this to-do list, how much it will cost for a 4000 sqft / 5 bed / 4 bath house? The majority of neighborhood houses are below 2000 sqft built in 50-60's selling for $100/sqft. The finish I am doing will be functional but non-fancy. 

The construction has been in halt for a few years. What I should look for? I need hire an engineer to look at the structure before signing the contract? I need go to the city to check if all the job already done was inspected and documented? 

I will appreciate any insights and help very much. I am very excited and also very nervous. I have been doing very well on buy and hold and have been always wanting to do flip. Please help me start.