if you are a beginning rehabber, this is a deal i would avoid, (unless you have experiences in other related areas or have researched this extensively or have asked experts i.e. structural engineers for their input), as 1) you don't know the prices your contractors would charge2) the estimated rehab costs are lumped under general categories (i.e. concrete, plumbing, electrical), but do you know which specifically/exactly you need to fix?

There is an extension cord from the second floor back porch leading down into the garage structure for powering the automatic garage door opener, which needs to be discontinued/removed (or have electricity properly installed to the garage by a licensed electrician).

Also, I am looking to do a couple of more flips this year and would like to find some GCs who have experience doing extensive reno's. 

During this period plus any extensions to it, the attorneys can cancel the contract for any reason. 

If the electrical panel is substandard (dangerous) and they are the one who hard wired an extension cord in the attic while cutting through a major purlin holding up the roof, and the garage door doesn't open due to damage (when they hit it with the car?)

Is this a real extension/renewal or a whole new lease?

Make sure your agent communicates the reasoning why your offer is low (extensive renovations are needed, place is old, layout needs work, building permits needed, etc.). 

If you think it is 750 rent then that is what it is; the rehab sounds extensive and pricey.

Do you have extensive experience in the trades?

With being in Chicago, I'm not really looking to buy a property that would need extensive work.