I think your estimates on what to charge for rent in Hastings is low.

Question for those of you who know,We currently use several credit cards (to of course gain points) for our apartment properties, which we spend over $150k a year or more on. 

I would not take that owner financing if possible, I don't know about your market but that interest rate is double a good cap rate in CA and more than most hard money lenders would charge. 

I was looking at gas and water paid by landlord and thought I could charge $55 each for gas and water as flat every month fee.

In addition, the PM charges their "new tenant fee" equivalent to one month of rent ($1000). 

So if you put $100k in a savings account with them, they might be able to use that $100k as the basis to lend out $500k... and charge interest on it.

I would venture to say that the benefit is protection; if all else fails, you pull that card to protect yourself. 

I can possibly help some and I won’t charge you anything

I am planing to put management company to manage my house, but it feels like they can charge any amount of money and i am in their hands.

I also am waiting on the Flyers and post cards to come back from the print shop.ps.