So looking into single family homes in the $400K range. 

They are also mulit-unit buildings valued in a similar range as the one you are looking at.

I'll handle rehab cost, management and yearly expenses etc...and would like to build a nation wide company consisting of low income-luxury buy and holds, fix and flips, commercial, development and eventually branch out to vacation rentals as well.  

Check out this link for the upcoming California November ballot --> "Justice for Renters Act" Essentially, they're trying to implement rent control state wide.

There has always been a wide range of commissions.

Where I live, just south of Atlanta, GA it's approximately 150 per sq ft to build, that's going to vary widely by the market though.

Range bound since 2021.

That's a wide spread. 

If you are being charged $400 they are probably using a licensed plumber with higher rates.From HomeDepot.com - The average cost of toilet installation ranges from $185 to $400 for all labor and materials.

Hi all,I have a ditch which is 150 feet wide, 100 feet long and 2 feet deep in the back with a city catch basin in the middle.