Interior, half the walls and ceilings are missing (lots of drywall). 

I just paid about $2k to do a whole house but that included painting the walls a lighter color and repairing all of the small cracks and holes from the previous owner hanging pictures and shelves all over the walls. 

And I'd like some feedback from someone to see where my thoughts have started going wrong.My mom lives in a duplex.

My  son rents 1/2 a duplex in Lakewood just across the river from Rocky River.

It is a top/bottom duplex where I am househacking in the bottom unit and rent out the top.

We found that all 4 walls in the basement are buckling in and the house needs to be lifted with a new foundation put in.

While there is a home office deduction in the tax code, it needs to be a separate, dedicated space (i.e. with walls around it) in your home used exclusively for business (i.e. no mixed use).  

Our goal is to start flipping houses now build some cash and then buy and hold duplexs. 

Fresh out of school, I just purchased my first duplex at 22 years old.

In my case with this 1920s house, it's going to prevent opening up the 1st floor, due to sitting between the wall separating the living room, and dining room.If it was on an exterior wall, I would still want to frame it in and make use of the space.