While there are some big positives (low maintenance), I don’t think they’re generally outweighed by the negatives of increasing HOA payments, reduced appreciation, and my biggest concern-changing HOA rules on rentals (what happens if the board changes the rental cap or eliminates rentals all together?). 

The potential liabilities for many people do not outweigh the better financing terms.

There is a 10 Year draw period and 15 year payback with the bank I used so that benefit alone far outweighs the risk of potential loss of the primary home. 

At what small amount does the "hassle" of getting a PML outweigh the benefits? 

If you're able to maintain the original ($800k) property plus the other properties you invest in with the cash-out refinance money, I think appreciation would outweigh this?

My goal is to diversify my credit while still keeping it above 750.Question 4: Does the benefits of using points for rehab materials on a Lowe's/ Home Depot credit card outweigh the negatives of a store credit card (high interest, etc...)?

You can save/earn on the commission side of course, potentially outweighing the cost to hang your license in a single transaction. 

The 2-3 years you experience negative will likely be outweighed by the gain in value. 

As much as I regret not buying 3 years ago, I think the appreciation opportunity here is far from over and will outweigh taxes and inflation (Am i wrong?). 

Not saying it doesn't have it's down sides, but for me the positives outweigh the negatives.