Your getting cheap money and putting very little cash into the deal while house hacking so I would go for it.  

As long as you are not using the line, you don't pay anything on it and when you do use it the payments are interest only so its cheap money.  

I want to acquire some land (with a damaged house) cheap and the owner wants to sell it cheap.  

That is simply and cheap if you do it yourself.

I think this area will be flat for several years, but still be a good area to get a lot of sq ft cheap and be in a safe area for homeowners.

Method of delivery is irrelevant as long as you receive it by midnight on the day it is due.

This can be typical of lower income neighborhoods, because if you take a look at the Top 10 Most Stolen Cars many of them are 90's imports like Honda, Toyota, and Nissan. 20 year old imports are cheap, and generally more reliable than domestic vehicles, which is why lower income areas tends to have more of them. 

I know interest on a car loan is relatively cheap (assuming your credit is decent) and that HELOC is a variable product.

I would normally do exactly what you said, except, I'm so cheap, I'd probably end up doing all the painting myself and paying the savings to my chiropractor after throwing my back out! 

The mental fallacy I see newbs making (whether it is SFRs or MFUs) is that lower costs units are lower risk ... in fact, the opposite tends to be true in my experience ... cheap units are higher risk, that is why they can only fetch such a low price.