Does anyone know how true this is and if mortgage rates will keep going up? 

There's a lot of moving parts here but it sounds to me that you owe them at most the original $150k + a conservative 8-10% interest per year (well above market rate).

I thought about doing cash out refi, but my current rate is 3.5%. 

And I could have lower income in that window after I semi-retire, before my mortgages are paid off to take advantage of a lower marginal tax rate

I recently started to have an interest in houses in Philadelphia and I noticed that there are some cheap houses there with squatters. 

With no experience you may have a bigger interest rate but if you have good margins on the hose, you should be OK.

- if everything is too cheap- if they mention more about their acquisition rather than how to maintain your property- if they only have two people in the office- they don't know how to manage property.- no bookkeeping.

It's an inexpensive market, but don't fall for cheap opportunities that look good on paper and details left out concerning the location and the vacancy rate. 

We then take the utility bills determine base rate split and usage rate. 

And most are variable rates.