I am trying to identify the advantages and disadvantages between the two and I am not adverse to spending more money upfront to form a solid foundation.

.- Contractor: someone who doesn’t mind walking through a property with me to estimate rehab costs and form a long term partnership.

You are paying the asset at pro forma. 

Excellent comment.There are only three reasons to form a partnership. 

Their offered pro formas had 6-7.5% cap rates if I am remembering correctly, but the assumptions were laughable.This is not my area of expertise but I would say you'd likely be looking in the 3.5-4.5% range.

Its not easy to go after a delinquent investor , they form a LLC , the property is encumbered with a first and a second , not much to go after .Going after a professional contractor is easy if you vetted them well .

I would have no issue buying a property with huge negative cash flow if my conservative pro forma showed a high rate of return or infinite return (most of our local RE has produced infinite return). 

Have you seen a t-12 or a pro forma?

When you run your pro forma how does it turn out?

Redfin will list it and there will be no PDFs telling people who much money they can make, how to house hack it, what the annual expenses are, if there is a pro forma rent based on upgrades they can do.