Wife and I have high credit score and we are high income earners (her W-2 & 1099 for me). 

Steady state, the property should generate about $12-13K in rental income monthly (I will likely live in the ADU to begin with, which would reduce the income of course).

I recognize we will not be able to offset active W2 income,  but if we do purchase an investment property that has some net positive cashflow, what are the types of tax benefits/offsets we can get? 

I was told it was “impossible” to get a conventional mortgage on an investment property with foreign income.

I was thinking of getting licensed to supplement income.

And since this is my main income source I don't mind spending some time on it every week.

The expected rental income is $925.

You acquire more capital in your position by (1) decreasing expenses, (if possible) and/or (2) increasing income.  

I didn't choose this profession per se; I'm actually disabled and needing to do this to supplement my income (although I have felt immense appreciation for the good tenants and proud of the way I continue to learn).Now I am in the process of my first eviction with regards to my current basement tenant (they're just not paying me rent, everything else is fine with this person but their financial excuses have been hard to keep track of since the beginning).  

With 200k in cash flow every year, you should be able to turn and use that income each year to buy more properties, but is that what your dad wants to do at 60?