Just make it is formal so you will not be too distracted.I am 59 years old and I have plenty to say.  

I just want to make sure I am understanding this right as we work towards a formal offer.

Following is how the ROBS 401k works: Because you directly rollover your IRA or former employer 401k, 403b, Keogh, SEP, SIMPLE, or other eligible account, to your new ROBS 401k  plan, which then funds your business, you incur no taxes or early distribution penalties.Unlike traditional 401k plans that allow for a 401k participant loan, that is, borrow up to 50% of the account balance not to exceed $50,000, the ROBS 401k for business financing plan allows you to use all of your retirement funds to fund your start-up business.The ROBS 401k funded corporation allows you to draw a reasonable salary from the business.ERISA 408(e), and ERISA Reg. 2550.408 list information regarding the use of 401k funds to invest in employer stock of the employer’s corporation.The IRS formally commented on the use of 401k business funds on Oct 1, 2008 by issuing IRS memo commenting that the use of retirement funds is not disallowed but continue to be reviewed by the IRS.The use of retirement funds for business funding entails the 401k purchasing stock shares in a C-Corporation.

Do I need to spend cycles focusing on formally structuring my business at this point?

There are countless ways to structure the deal but make sure you have a formal contract written up with an attorney bc I AM NOT A LAWYER NOR GIVE LEGAL ADVICE.

I told her already that the lease is binding and that only made things worse and she is now "formally intent on not renting the house".  

I have no formal experience in the industry, but became interested in real estate investing after participating in the ACE mentorship program.

Do I have to do anything to formally update the assignments for my notes?

Keep it all formal and be patient.

Then, follow up with formal notice once you have some kind of agreement, to make sure they know you mean it.