Newbie-In escrow on a two flat near United Center

[Scott McCarty]

Hello Bigger Pockets community. I think I may have bitten off more than I can chew. I am currently in escrow on a two flat near the United Center, a complete gut rehab. Before I went into escrow, I brought a contractor that I know thru the property & he expressed confidence that w/ a 300k reno budget we could have a nice duplex-ed up owners unit & a garden 2 bedroom rental.  

This budget includes a new roof, all mechanical, plumbing, electric, new windows, new garage & significant work to the garden unit. Currently the basement has a wood floor over a dirt surface.  It appears that it hasn't been touched since it was built in 1885 & the floor is rotted thru in a few spots. We saw water incursion in the basement from an old chimney flue & it appears to be the cause of the rot.  We are going to have to rip it all out & most likely pour concrete. 

We went thru a second time two days ago to recheck the foundation & it appears to be in good shape. No cracks visible from the outside, floors on the main & second floor didn't have any weird sloping issues. Door frames & doors all lined up as they should. We did see that some of the mortar between the stones near the leaking chimney flue will need to be addressed, but my contractor didn't think it would be budget breaker.

The total square footage including the garden apt would be about 2300 sq feet. Does this seem like a reasonable budget for the square footage & issues we currently are addressing? 

Also, I had an architect walk the property to get a rough estimate of what his costs would be for a project like that. He is coming in at 7500 w/ the caveat that he may need to bring in a structural engineer at an additional cost, possibly another 1k. Additionally, he is expecting permit fees to run 3-4k. Do these numbers sound reasonable? 

I appreciate any and all advice. Starting to wonder if I should run away screaming...