I just want enough money to travel the world and give back to causes I care for. 

We are able to borrow the money at 5%, however the lender also wants a small portion of cashflow (not equity) from each property we buy.

Oakland is not a hands off market, but done right can make money.

Friends and family is where I started looking for private money, as there was already a trust factor there.

Conversely, I also know people who find communicating with guests and cleaners to be incredibly draining, they don't know the first thing about managing an STR nor does it particularly interest them, and they would rather spend their time making money in their main job rather than taking on a side hustle that they may not be able to do as effectively.

But I’m nervous to invest their money as I’m pretty new and an amateur to investing.

Should I just hire collection agency for the money owed? 

Often old houses have some rooms which are not flat even if they appear to be so to the eye.Also, when you are spending money, you want to make the biggest difference for the cost.

For someone who is just operating a property or two through a single LLC it would be hard to justify spending a massive amount of money creating an elaborate asset protection strategy.

If you hire PM on your first property, you are just tossing money away.