Traditional conventional mortgage for an owner occupied property.

Since you occupy one unit- that unit will qualify for the 2/5 year rule (if you've lived there for at least 2 years) for the 121 exclusion and be tax free. 

And I plan to occupy the SFH after purchase. 

Purchase price: $110,000 Cash invested: $33,852 Closed 09/23/2021- Tenant occupied duplex with each unit currently renting for $650/mo.

I rarely get an inspection on my properties since they are vacant when I am looking at them, but because this unit was occupied and I don't like being intrusive, I got an inspection with an awesome company.

In most of the Denver Metro Area, STRs are limited to owner-occupied properties, and a lot of areas require them to be licensed and permitted as well.

What does cash flow look like if it were to be used as an income-producing property vs. an owner-occupied property- how would maintenance, taxes, and insurance cost change with each different scenario? 

Doctor loans that we have are only for owner occupied PharmD is okay.

. $20k isn't going to get you a small MF in many markets unless you get a low-down, owner occupied loan.

Fully occupied rent would be ~$1600 ($800 each unit).