find this sooner or later, But, I would get a series of three or four reputable contractors to access the situation. You mentioned a few of the most major concerns of the house. These are big buck consumers right up front.
Once you get some estimates and some professional input, consider over runs, time delays, material cost increases and budget another 25% over what is quoted just for these.
Be careful these days about fast turnover sales yielding fast quick bucks. This is not the 70's when that actually did happen.