You may make really good money this summer (and that’s really good money) but a bank is unlikely to give you a loan if you don’t have consistent income, or a co-signer.So if you wanted to buy anything like a rental you’d likely have to wait until after you graduate and got a full time job.  

Each one is different.As far as contracts, if you work with a  reputable wholesaler (may be under a co-wholesaling agreement), you should be able to see how he/she writes their contracts. 

I do manage the property remotely and only come to town to solve a significant problem that is too much to ask of a co-host.

Is the septic and well inspection necessary for getting a CO.

I can’t say I know anything about how things are done in Michigan, but I would think a ‘Certificate of Occupancy’ is different than a ‘Rental Certificate’ A CO is an inspection and determination that a space is habitable.

A co-wholesaling marketing agreement that makes the birddog a pricipal.

I have to be honest, we are still waiting on some clarification from IRS on that area, but you claiming this is just a co-ownership of the property might not bring your rental activity up the level of the "qualified Trade or business level" that is required for 20% deduction. 

For example, the duplex that I am strongly considering buying from a co-worker can be purchased for 45k.

That's unrelated though, so I have a co worker who is letting someone he doesn't know prior.

Caleb, I forgot to mention that I do have a job so I probably wouldn’t need a co-signer.