I had a taxable account, which I eventually just blew out on the secondary market to get the money back because the hassle was too high.I do still invest in a Roth IRA (takes out the hassle of taxes makes the returns manageable) and utilize it as the "bond component" in my Roth since bond prices have been in the toilet lately.

I don't know the limit but you are getting a 3.5 loan so get a 4 plex or one that can be build out to 4+ or an ADU (value added component) so you can get some nice returns at exchange time. 

I am an authorized Goodman dealer and I would not sell a gas furnace (installed for the third quote)...this does not include the a/c unit, which is the expensive component in all this.Long story short, I would sell a furnace/compressor (entire system) 3.5 ton for closer to $10k installed...The $6500-7400 may be in alignment with your market...but, if the lowball price is legit, why not?...

However, the amount of the interest rate and inflation rate is a more important factor.In an inflationary cycle not all components of the economy rise by the same inflation rate.

All electric has been updated, plumbing updated, plaster walls have been replaced with drywall, has a metal roof, has 5ish yr old heating/air.I am not as familiar with structural components to a home, which makes me skeptical on such a old home. 

In SFR or smaller MFU there is an emotional component because people are after all "going to live there".

You need detailed measurements so you can accurately estimate your materials for each building component, down to the last screw - I assumed a 4 room structure, the costs will go up a tad if there are more walls in the layout.I can tell from the pics that the framing is not all done - you have a header dangling out there without support.

This is because while the interest component grows smaller with each payment, the total amount of investment capital deployed is reduced more rapidly. 

(I'll assume you are not modifying the structural components of the building...columns/load bearing walls) Sounds like you need a licensed electrician ...and you will be good.

syndications if your accredited can be good as well. but the sponsor is the key component here.. more important than the underlying asset.I have personal knowledge of realty mogul and realty shares.. both companies that boot strapped it and are now doing quite well.