HELOC vs Cash out Refi? And when is the right time to cash out?

[Katherine S.]

We own 3 identical homes on the same block, purchased 3/2015, 12/2015, and 10/2016.  The first was a short sale, and was purchased as a place for our daughter to live in while going to college.  She pays rent that is basically B/E.

The prices on homes just like these in the neighborhood has gone insane in the past couple months, and they are selling in less than a day.  I'd like to take some cash out of these homes to use to purchase more property, but have two questions.

First, should I wait until the property values have increased enough that I could take out my entire initial investment before doing the cash out? This would eliminate the last house, and probably the second one because of the improvements we put into it, although it would be close. This seems to me to be the most sensible thing, though, considering the cost of doing the refi. I would only want to go to 75% LTV.

Second, we have the most equity in the first house, well over our initial investment. However, if I refi, I will be in a negative cash flow situation because my daughter can't afford to increase her rent while she's still in school. I'm interested in using the cash to help purchase BRRRR properties, which if done properly would return my initial investment, which I could use to pay off the HELOC, but I would be locked in perpetuity (albeit at a lower rate) if I refi. So which is the best approach? Can you even get a HELOC on an investment property?

I'm kind of answering my own questions, but I'd appreciate your input.