-does depreciation work the same in the duplex since i am living in one side and renting the other?

One unit has nearly the full back yard and has a lot of water irrigation.

I am purchasing a Duplex 5bd/2bth each side, and planned to house hack one side and rent out the rooms. 1.

Columbus OH is one, especially now with so many companies like Intel, Honda, Amazon, Google, etc. moving and developing here.

Make sure that you have all your notes, pictures, work orders reports etc...keeep copious notes, its one of the most important items.

Seller financing hasn't worked, but seller came off price to $100k (was $125k). 930 sq ft 2br 1ba raised foundation on 1/2 acre - lake Livingston on one end of the street and Trinity River on the other end of the street.How do we move forward to cover $100k mortgage? 

Given the details here I'd say no, you should take any development thoughts off the table because to do that is not something one simply learns over night, there is a lot to it. $209k is very cheap for 40 acres, so that offer could be a person interested for hunting land and nothing I'd get excited over, and I wouldn't assume it means anything other than you could sell it for $209k. 

One tenant claims people are breaking into the house and hitting her at night.

A lot of little items, a big one being plumbing but I got someone to check the lines and all was good.

Good news is that we have one signed LOI already and negotiating on another one - a major national chain.