If you have that much cash, buy rentals with a DSCR loan, and then use that income to qualify for the primary residence.

If you were looking to use the rental income from your roommates to help you qualify then you would need claim it. 

The other good news is you ca use the rents of the other units as income to qualify so you can essentially qualify for a higher home price.That sets up your next investment property as you move out its now a 2-4 unit with multiple doors bringing in more income. 

Will this property qualify for all the tax benefits of STR?

In our market, it's not a deal killer, but you have to take into consideration a lower qualified tenant, and you will not be able to achieve market rents.

Near Centerville/Kettering you can find some great A/B class properties with good tenants.In terms of cash vs financing, if one of you is a US citizen, you can still qualify for a conventional loan with your current income.

I'm going to run some details by you and I'd like all of you who feel you are qualified to advise me so I can learn how to properly analyze these deals and be more cognizant of potential pitfalls/mistakes:So, I found this property off market in a Chicago real estate investment group.

Also, a great QI (Qualified Intermediary) is @Dave Foster.

However, she wants you to qualify him based on her record, even though she is not living there.

I'm not familiar with non qualified mortgages, I'd generally assume the less mainstream/vanilla the borrower, the higher the costs and rates, why would non QM instead be lower costs?