My plan is to live on the upper unit and rent a room out to a buddy and turn the lower unit into a midterm rental.

It's a riskier loan given you do not carry a social security, no US credit & no experience.Due to increased risk comes mitigation (Lower LTV & Higher Rates)

I believe the appreciation has been great over the past couple of years and prices are lower than in major areas like Miami metroplex or Charlotte.

Than AFTER that base-line cleanup action is done which part of it is to establish access for all others, than things get into the next lower level of details. 

Now I have two vacancies and lower rents than when we started. 

PROS of a Solo 401(k) with no Custodian: 1) Freedom of checkbook control, ability to more easily move funds in and out of a bank account in the name of the Solo 401(k). 2) In some cases, lower fees. 3) Ability to more easily link your Solo 401(k) to bank account systems like rental property management systems, or if investing in real estate syndication platforms. 

Fannie May is a good option for a lower downpayment.

Thus, my taxes should be higher because of the income I generate.If I pay off the primary, I'll increase the amount I'm able to save monthly not having the mortgage, while also keeping the income generation lower on the rental because the mortgage remains open.Any thoughts would be appreciated! 

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Quote from @Dan Lucchesi: Quote from @John Underwood: Lower price and advertise in more placed.I even get an occasional booking from a perpetual free Craig's List ad.