Apartments are identical other than upgraded appliances, re-grouted bathrooms, and kitchen backsplash (along with much nicer paint colors).

For example, suppose you have 10 "identical" properties.

If the units are identical then 50% of the sales price would be allocated to primary residence and 50% to investment. 

For a regular rental that someone got a steal on and just bought way below market then yes I agree with you on this approach.

NoDo not do itPLENTY of selective scammers who are GREAT with the majority of customers and they use them for their rwferrances and outright steal from the other customersI would Drop that contractor like a hot potato. 

A little bit of digging, this guy, just buys the house, and starts to give me money directly into my bank account.So I decided to steal his money and run.

That is nothing short of stealing.

This prevents any accusations of me stealing money from a tenant or messing up their payment schedule.You could give your tenants a deposit slip and they can set up direct deposit or deposit the payment manually at your bank.  

Meaning the duplex I got for $40k, its identical neighbor sold for $79k, 2 weeks ago. 

I know where they live so why should they not know where I live.I have been on internet forums for 15+ years and have tried to never provided any accurate information that would give away my identity.