I think my best bet is to find a flexible bank and bring in the down payment as debt.

I know I annoy them sometimes but it is kind of like your doctor pushing you to stop downing burgers and fries because it is affecting your physical health. 

I would bet that the majority of real estate investors have an equity portfolio where they have no clue about what the companies that they hold do or how they make money.  

That would be your best bet to kind of get the best of both worlds.

Get the lock that also has a hole for a physical key  and then have a good ole fashion lockbox with the key in it as a back up Example of yale with key Dont get one like this without a keyGOOD LUCK!

After a brief engagement, they understood never to come around that building again.I yanked a few others out, with less physical force, but I knew the risks.

If it's an investment property, then I think your best bet would be to move the property into an LLC with you and your parents.

I've also been told off-market deals are often the best bet but am clueless about them... 

Your best bet is to talk with the seller about financing options. 

I'll bet you that no one in this blog know what the FIRE Strategy is.