You can definitely benefit from having a retirement account that you are in total control.If you don't have any retirement accounts to rollover - then you will be limited to contributions of only $5,500 per year, so in this case you can probably have a conventional account (not self-directed) so that you can build enough funds before you self-direct.However, being a real estate agent makes you self-employed and therefore eligible for a self-directed Solo 401k, which is much more powerful then SD IRA.

Would she do nothing and it then roll over to her name and still cover her rent or would she have to reapply immediately?

I just had an investor roll over some money before the stock market dip a couple months ago and it saved him a lot of money.I agree with you, multifamily properties are a great start and I like your plan.

In addition to making new contributions to a Solo 401k, you could rollover an existing tax-deferred retirement plan into that Solo 401k.On the other side of the equation is the use of a self directed plan.  

I'm employed full time with roughly 45k gross income, have about 20K in savings and 260K in an IRA that I could roll over to a self directed or solo 401K.

C Corp & use a ROBS (roll over business startup)- Expensive setup and yearly costs but unlocks my IRA funds to create one large pool of capital.  

Keep in mind, though, that you usually only can roll over your 401 if you no longer work with the company or something. 

So we are certain that there is no way to rollover gain on personal residence say if you rented out rooms in the Owner occupied property, right?

I have really never seen a county health department roll over if a system does not meet their approvals.. but again I might be missing something.Just think about people that had to tear homes down in the Gorge because the Gorge commission came back and said they built in the scenic area even though they got permits.. those cases were litigated to the tune of Hundreds of thousands of dollars of legal fee's. 

They educate investors on the process of self-directed investing or assist in setting up single-member LLCs for either “check-book control” or to purchase a franchise or ROBS (Roll-Over Business Startup).