According to the article, she is still looking for permanent home for her family.  

And according to the CA Department of insurance it would be inaccurate and unethical to disguise yourself as financial adviser if all you do is sell permanent life insurance products.

She has a new fulltime job lined up which I have verified is a permanent position where she will be making more than 4x the rent.

I agree and I don't intend to have just one property per LLC permanently.

Now if you define failure as a permanent state of a lack of success, then I think its arguable.The fact is that you WILL make mistakes and you will fail, but by persevering through and learning from the mistake/failure you can develop yourself that much more.

I know many people who work with ITIN numbers as they have work visas and working towards getting permanent residency.

If the markets get better, they can refi to a lower, more permanent financing, if not, they can ride the wave or sell.It's all about your plan and anticipating what might happen so you can mitigate losses and assessing how much risk you are willing to take. 

eventually I’d like to build a permanent primary residence for my family on this land, and convert the first modular home we would rent into an ADU.

State law varies on the requirements for an installed feature to become permanent.

Here in NJ, unless you're buying As Is, the seller or buyer has to be able to obtain a permanent (not a temporary) CO for the property as a condition for selling or buying the property.So if you're NOT purchasing as is AND the municipality is requiring that you get rid of the illegal living unit in order to issue the CO, then the seller must do what is needed.