636K can vary to some higher priced areas in the country, but the majority of the country falls ~417K.

The town sits between a major city, and a major east coast summer vacation area. (60 miles each way).  

I've had 3 different plumbers look at it and all are saying this should have never passed inspection in the first place.To try to brief, the house had a brand new HVAC system with the tankless wall units - this was actually one of the major reason I wanted the house as I currently look for my turnkey properties.  

First make sure that you get a Real Estate Brokers License.2nd, look at the contracts and see who owns the properties, and does one person own a majority of the houses.Are the contracts assignable?

And if you add in other major mechanical things...it might run up to $10k...also on the lower rent range you will need to have a higher percentage because while a roof's cost will vary by the size and class of the property...things like heat and air and water heater and appliances are relatively fixed therefore being a larger percentage of your rent.

Are "major" foundation issues a definite "NO" when looking for a fixer upper?

I am an engineer and currently work for a major ag/construction/lawn equipment manufacturer (I'll leave it to you to guess which one) at one of their factories in my area. 

Houston is finally starting to get some respect as we get a major influx of people coming from other cities looking for lower taxes and better quality of life.

The majority of lending sites seem to cater to home owners.

I did have a home inspection company that is well know around here inspect everything and they did say anything was major with Chimney