The cons - very hard to cash flow off the bat, especially with a low down payment and...

., if the housemate who’s leaving was covering 75% of your mortgage payment, that could be a major problem…but if they were only covering a small portion of the mortgage and/or they’re easily replaceable, it might not be much of an issue).Moderately important: anticipate and manage your relationship with the housemate tenants.

Another option is to get an interest only loan, which reduces the payment amount and thus allows for more cashflow.

Once you do, begin the termination for non-payment process that your lease (hopefully) spells out.   

So a big monthly payment you're thinking?

But multiple credit cars, car payment, rent is a no go.I've had a few tenants that went thru foreclosure when the market crashed, and want to rebuild.

If they truly had your best interests at heart, they would defer the payments until you made a profit. 

Several methods come to mind for the ADU.   1) a regular or periodically adjusted flat fee (based on an estimated usage); 2) factored into the rent (essentially the same as a flat fee); 3) percentage proportionally based on sqft. 

This will have a significant impact on your loans, especially on lower balance loans or loans with low payments. 

Here are some excellent practices to remember if you decide to employ the home hacking method again:1.