A 50k addition (adding an extra bath and bedroom) would likely add 75k of value to the house. 

from those I know the way they got going was to buy a 4 plex when it went up in value sell and buy an 8 when it went up sell buy a 16  then a 40 then 100 extra and you need no partners.. you grow it organically. however of course this is not pay 40k and your instantly an apartment owner..

maybe just me, dont go cheap on TP. you can buy inexpensive, but make sure it doesnt feel cheap. its worth an extra couple of dollars so guests dont remember that everything felt cheap

If interest rates fall later, refinancing again might require you to bring extra funds to the table, which could impact your overall investment strategy.

Vs her current super-chill life, get's special discounts all over the place for being "too poor" and all the while can work cash jobs when wants extra, keeps her bank account low, plays the game to get here "free ride". 

It seems like it basically up to you to do the math on how much more you will potentially make selling each unit individually and then deciding if that extra $$$ is worth the number of extra hours you will spend.

To process a new owner payment the system takes an extra week or two.

Section 8 can definitely cause extra headaches like the longer wait times to get a tenant in there, the inspections, and the incompetent CMHA office you can never get a hold of.  

Right now I'm just looking at properties all over the place learning how to analyze a property etc but as somebody that is looking to make their first investment, i want to avoid if possible the extra outlays that can potentially come with an older house. 

You might find that they could charge enough extra rent to pay for themselves.