There's a lot of knowledgeable folks to learn from and I'm also happy to share the mistakes I've made to prevent it from happening to others.

Any suggestions on how to prevent UD tenants from trashing the place?

If so, would that prevent me from taking out another HELOC after I paid it back?

The CC&R clearly prevents it along with an acknowledgement of the rules when a tenant signs up.  

Have you looked into whether this will prevent you from taking a 3.5% down loan in the future? 

Sell the lead to a real wholesaler who will pay you a finders fee if you don't have time to learn to do it yourself.Since a friend is involved I would do a double close to prevent him from finding out how much you made him overpay for the property.

Then using a long-nap roller, keeping a wet edge as you're painting to prevent overlap lines, and keeping the shingles just ever-so-slightly damp.

I am reluctant to admit that I have proven anything.But.....the advice I gave regarding how not to discriminate is valuable in that it will  prevent landlords from selecting tenants out of fear which is something far to many landlords do at their peril.The value of advice is not in the advice itself but rather how one uses that advice.

I posted in your thread discussion too, as you know.Getting any kind of insurance after the fact may be avoided if delayed if you are not prevented from receiving the benefits that you wish to receive now. 

My bank has been sending my HVAC guy an annual check for a preventive maintenance contract renewal automatically on March 15 for the past six years.