I'm completely new to these calculators and may be overly cautious with my cost estimates since I don't currently have any experience with BRRRR.

Ask this person for a chance to pull this whole thing together.

(The house was rented out for 7 years prior without any issues.)The new owners said they are giving me a chance to make things right. 

While you vacancy might be close to zero, I like you estimated 10%.The water and electricity seems high, it might be right because of the laundry.Anyways, those are my quick thoughts.

I guess I'll call a local realtor and pick their brain for some ideas, and at least get an estimate of what it could possibly sell for.

Give the man a chance!

Thats exactly how I remember the street I grew up on lol  A lot of variance but I think Trevor Baker has a chance for a great deal but should try to get as many comparables as possible first!  

Rent estimates do not take into consideration the desires or local tenants such as the perception of the area, schools, etc.

Not sure I subscribe to that theory...they didn't pay when they were the owners, chances are good they aren't going to pay as tenants.

Learn how to accurately estimate renovation costs and find an agent to do comps for you.