I built a 1500 sq ft home this year and it ran us about $90-95 a foot (not counting lot cost).

Did you count yourself living there or calculate in the rent as if you weren't?

In my opinion, once you start getting down into <$200/mo in cash flow, in my opinion that's not enough to count on. 

We likely will need to up our tenant key count soon but we switched to LL Locks around 2012 (maybe it was 2013).  6 sets of tenant keys for 6 years with 19 units, I will take that any time (but 8 units of the 17 LTR units have not been turned over since switching to LL Locks - very slow turn over).I would investigate the option in the link you provided and compare the features with LLL to determine if the one in the link supports everything LLL supports. 

I disagree with the people above worrying about bathroom count.

Count the costs.

Also the layouts, are they true 2-bedrooms or is a "bonus space" counting as a 2nd bedroom that almost nobody would use as such? 

Because we cap our unit count we offer a much more owner focused service and our clients love it. 

This was my first BRRR (my second rental overall, but my first rental doesn't really count because I bought it as a primary residence in 2005, moved out in 2015 and it was underwater and couldn't sell it due to market crash, so now its a rental that barely breaks even). 

Also, interest rates are raising pretty fast so I wouldn't count on anything less than a 6% interest rate.