Too many varying opinions with sound logic on both sides in this forum regarding traditional velocity banking.First position HELOC ... 

I have one I have drafted up but would love to compare against others.What are some items you always included in your MTR rental agreements?

Reassess whether you need the home warranty, flood insurance, or other items.

I would try to buy properties starting at a specific date so not large ticket items come up.

So I'm guessing it might depend on your state laws and personal situation. and make sure you know of any sticky items that would eliminate the protection you get from the LLC.

As a side note typically I do not use my deferred tax dollars to invest in traditional real estate as the benefits (depreciation etc) are all lost when using a self directed IRA - My guess is build to rent will provide little to no cash flow to build the account - it will all be locked in the property. 

For the ballon payment I would plan to refinance into a traditional 30 year loan.

From the sentiment of your post it seems like you're viewing the buyers as strictly investors when they may lean more towards traditional homeowners looking for a quality of life improvement or an improvement on their current financial situation today.Let's say the buyer pays 465k and has a 5% interest rate.

This property needed an extreme amount of clean up and haul away of items left behind.

Some kinds of auctions allow you similar protections as a traditional sale.