I need to understand how I can waive any liability on me if their kid, dog, friend, relative or neighbor drowns in the pool.

This includes PAR and NAR fees. you may be able to find a board/broker that does not require PAR/NAR which could save about $300/year but would limit your other benefits.

I'm not sure how you are going to limit them to responsible borrowers only, but if you figure it out then you can probably just limit them from all forms of borrowing.

This is in Indianapolis not rural areas with limited Google Data. 

I am looking into either house hacking/ investing into rental properties as I am a college student with limited funds.

On BP they talk about the BRRRR but isn't that counting towards your 10 limits?

That would be the absolute limit of my compassion.

The profit margins on the flips aren't as high as when I had the employees but my liability is way less.

Is there a way to do this while legally protecting myself from liability (i.e. having them sign a waiver)?

I note that you asked specifically about “cash-flows”, which has multiple components each treated differently for tax purposes.In general, you can start with NOI, next you have debt service and cap ex, which can get you to cash-flows.The interest portion of your debt service is tax deductible (possible subject to limitations) and the principal portion is not because you get basis in the asset for the loan principal, which generates a depreciation deduction.Similarly, cap ex is generally not deductible currently but the expenditure is capitalized and depreciated, similar to the initial basis in the asset.In summary, you have cash and non-cash tax items that cause your taxable income to differ from your cash-flows and taxable income * tax rate determines your tax liability.