10 Unit package in Philly - Analysis input requested!

[Bryan Satter]

Good morning BP! Happy to hear your thoughts on the following:

10 units (9 buildings). Almost all section 8 housing, with leases. Purchase price + closing =$820,000. Assumed appraisal $890,000

Verifiable current rents = $10,180/month

How to pay for it: seller financing for $400,000 @ 10% for 12 months. I will borrow $450,000 (to include some capX reserves) from friends and family and pay them a blended interest rate, averaging 8% for 3 years with an escalator to 10% if I renew for years 4 and 5. 

The plan is to get a mortgage after year 1 to cash out the seller. As for cashing out the investors, either refi after 2 years to see what else can be pulled out to pay them back, or worst case scenario, after year 4, sell 2-3 properties to pay them back.

Does this seem like a reasonable exit strategy - namely seeing if I can pay back investors via refi, or selling off part of package if necessary in 4-5 years? Doing so essentially enables me to own the properties without using any of my own $$. Does this seem unrealistic? 
Appreciate the insight!!

Just for more analysis  - using these numbers, "profit" after vacancy, taxes, insurance, interest and 20% for repairs/CapX reserves is 2% of gross rents for year 1. Once owner is bought out after year 1, it increases to 11% for year 2...