I am not going to minimize what you do and say, "Oh, you're lucky, etc" because it takes a lot of time, energy and money to do what you do; especially in this EN FUEGO market. 

Add 2 or 3 drywall layers for best results.Read this test (look at test #5)http://www.mjm.qc.ca/publications/en/177881_Floor-CeilingAssemblies.pdfThe most critical mistake that people make is not leaving a 1/8" gap between the new ceiling and the wall.  

An en suite probably isn't worth it as much because the other properties in the neighborhood probably don't have an en suite either.

Here are some of major players...http://www.marcusmillichap.comhttp://www.svn.comhttp://www.lee-associates.comhttp://www.us.jll.com/united-states/en-us

@Dan Cho, @Ned Carey;  These are the two common investments strategies and each fills the assumptions and needs of those using them. 

The problem for flipping is the non-standard SIC codes for this activity[sic:- standard industry codes per IRS]see  http://siccode.com/en/siccode/list/directory

Zillow uses Checkr and Checkr seems to have a system to handle this. https://help.checkr.com/hc/en-us/articles/216873808-The-Adverse-Action-process-Deciding-not-to-move-forward-with-a-candidate3.

You can figure out your financial readiness by reading the CMHC website: http://www.cmhc-schl.gc.ca/en/co/buho/hostst/hosts...As a mortgage broker in Canada, I have clients whose income is commissioned based or from tips (like you) and have qualified for a mortgage.

But I don’t have enough direct insight into their operations  to say conclusively.Lastly, I don’t think city loving people are going to run off en mass from prime cities and into the burbs (although sentiment in NYC may differ as it was hit hard with corona).  

Dave Charron I vote convert the downstairs den to a bedroom and then convert the 4th bedroom upstairs to an en suite master bath.That way you keep 4 bedrooms but also add a highly desirable en suite.