You are not asking to raise his rent you are telling him your are raising it.You should also not be supplementing his rent.

When the proceeding supplemental for interrogatories  was served, it was I who sent the forms to the Sheriff and paid him for serving these forms. 

I started researching real estate investing when my mother's rent started going up and I figured the only way to not end up supplementing her at some point was to purchase something in order to create "rent control" so to speak.

I’d like to supplement my income with passive cash flow and continue to re-invest to give myself the opportunity to retire early.I currently have $20k saved up as cash, and $10k in an emergency fund that I could dip slightly into if required.

That's what investors do.But is investing what you want to absorb you or are you a casual investor who loves his career and is investing to supplement or prepare for the next phase of life when it happens?

I have a full-time job in marketing, but I'm looking to supplement and eventually replace office work with investing. 

Keep in mind if you are in value add plays, CoC and IRR can go up as a result of refinancing at the end of the renovation period or if a supplemental loan is applied as well.  

Personally we are hoping to do a mixture of both buy and holds (BRRR), but and hold to create constant cash flow on into retirement and supplement it with flips.

You are already supplementing their rent to add 2 more tenants that are going to be nothing but drama is not worth the effort.

Then my wife started a business marketing nutritional supplements,, and we decided to do it under the same corporate umbrella as well, using my S Corp.