That's the typical recommended approach because you can rinse-and-repeat but it is not necessary at all to participate in the manifold benefits of house-hacking.My family of 4 moved into a house-hack 2.5 years ago with a calendar on the wall marking down the 365 days we HAD to be there. 

While most ordinary interest income is exempt from UBIT if there is some sort of profit participation element there might be UBIT tax owed.

Definitely seeing it -- all you have to do is look at  the institutional investors that are building the new apartment buildings here in Pinellas.  

IRS rules prohibited any direct or indirect benefit for such person from his/her retirement account, and as such you are not allowed to furnish any service, goods or facilities to your 401k:https://www.irs.gov/retirement-plans/plan-particip...While in some instances it might be possible to get into an investment together with a disqualified person you must be very careful!

There is no ‘middle man’.As the trustee of the plan you go to any financial institution of your choice (a bank, credit union, brokerage firm such as Schwab of Fidelity) and open non-custodial account for a trust.You request a direct rollover from your Traditional IRA or former employer 401k and in few days receive a check payable to (for example) ABC Solo 401k Plan FBO John Doe.You deposit this check into newly established bank account for the Solo 401k Trust.Now that your plan is funded you can make investments as simple as writing a check.

I made the mistake of trying to get a HELOC, not realizing that most banks won't do it for a "rental" property (our insurance showed the home as such) and/or a home that is mortgaged through a non-financial institution (the mortgage is 0% interest with my mom-woohoo!). 

This can include real estate agents, property managers, contractors, lenders, attorneys, accountants, and experienced real estate investors.By participating in the BP forums, your local real estate investment groups, and other meet up groups you may be able to find a partner to invest in real estate.

Use them to understand A) what the ARVs are for rehabs (realtor), B) How much the rehab will cost and time to complete (contractor), and so on and do the go it yourself route3)Participate in a syndication if you qualify and see how they operate so you can mimic it going forward.Best of luck 

You get compensated for finding the deal and they get to participate in a deal they wouldn't have otherwise had the opportunity to do so!

Here are a couple of things that haven't been said. 1) According to the Hoover Institute, more than 13,000 businesses have left California in the last 10 years.