For example, if I take a loan from 10 different friends and family members, all secured by the property that I'm buying, is this something the title company would accept at closing?

Yes, to clarify with a real life example, bought a place for $125k and the bank required me to have 25% down ($31.5k). 

Escalation offer example below:SPECIAL STIPULATIONS: The following Special Stipulations, if conflicting with any exhibit, addendum, or preceding paragraph (including any changes thereto made by the parties), shall control:Buyer's purchase price offer is $x with $x Seller's Contribution at closing; however, if Seller receives one or more higher NET offers before this offer is accepted, then this offer is increased by $x above the other acceptable offer up to $x.

Example: You have $500K in your IRA, buy a $100K rental with IRA funds and title it with your IRA (so you now have $400K cash in the IRA and the $100K house). 

As an example, getting 20K to work to generate 2K in profit, $600+ will get lost to the administration costs. 

Some people do but they usually will invest out of the area for example if you do the math living in San Francisco your money will work harder for you if you rent in San Francisco and invest in other parts of the country as opposed to owning in San Francisco. 

For example, I purchased one of mine for $175k, and a month later the same floorplan a few houses down was listed at $280k. 

For example, if there's a plumbing leak and they say they can handle it, politely decline and send your professional plumber over instead (or do it yourself).Always keep the relationship business-like.

Give the whole thing a fresh coat of paint, and replace the outlets and switches if they aren't white and clean.  

Just for example, I've been running models that use that mode of financing, however (at least in Vegas), I have not found deals with enough meat on the bone to use HML to BRRRR the property.