You can also check their reviews online at Google, Facebook, or Yelp.

There are some of the new online lending platforms that might work, but again I think probably what they will charge you vs what you might make is not a good option. 

Others I re-financed to get cash.

Check out other online guides available here: https://www.biggerpockets.com/guides3.

Can someone explain how using the Heloc to purchase the property with cash, then rehabbing it, then renting it out and then refinancing the home would benefit them in this scenario?

If everyone could sit back, find real values on line, and make offers based on those values everyone would get rich flipping properties.  

Join in some local groups or check online listings such as Zillow, Redfin, etc.If you're also in need of funds for your real estate venture don't hesitate to reach me.

Join local real estate investment clubs, attend seminars, or engage in online forums to stay updated on the latest trends and strategies.Remember, real estate investing is not a get-rich-quick scheme.

Searching online, it seems all the property managers have awful reviews. 

The information he offers is readily available for free on BiggerPockets or online.