I have a friend who works for a well-renowned construction company in our town who has offered to be our general contractor at a discount (only charging us 8% vs. the standard 15%) and "teach me the ropes"/make the right introductions so that I can repeat this on my own in the future. 

Written by attorney investors, it's full of practical advice about the management of investment property, has sample forms that can be edited, and - most importantly - tells you what your primary state laws are and where you can read them.

With this being a buy and hold I am tempted to go in and do the full gut and fix everything up to current standards even though it's not required.

As a retired CPA, I have seen more than my share of bankrupted RE investors who were over leveraged with many properties.All the more reason to emphasize developing good due diligence practices, having some skin in the game and staying on top of legal requirements, maintenance, finance and tenant screening criteria.

Just implement the same standards across the board and you can be sucessful with it. 

If you where going to be able to recreate the orginal layout, you would of been able to do so by the clues left behind by remaining framing, be it the "honey" holes where the toliets once where, the sizes of the holes in the joist would indicate what pipes ran where be it hot and cold supply, toliets, showers and other industry standard tell tale clues. 

I hate the practice.

@Stepan Fedetskiy section 8 can be good option if you have a good PM who maintains the property in good shape all the time as per the needed standards. best part is govt pays a portion of the rents so you dont have to chase tenants, downside the upkeep of the unit will eat up appx 20%. so its little tricky..sounds good on paper but when you go through one you will get an idea. i had 4-5 section 8's , 3 of them had no issues, but 1 of them had lot of issues and ate up all the profits.  

Or, you could just sell, now, today, standard sale.

This non-profit specializes in fair housing practices/housing discrimination on Long Island, "Our mission is the elimination of unlawful housing discrimination and promotion of decent and affordable housing through advocacy and education."