I wonder if Realtor dot com is licensed then in all 50 states.. so they can legally take a slice of the commish ?

You need to consult your local laws to see what the legal amount of time is and decide for yourself if that's "reasonable."

Are you up to date on all of your licensing and permitting to legally rent this duplex?  

My advice for establishing a trusting wholesale relationship is to get properties under contract and controlled legally, after which you can start having a conversation about agreements.

The good thing about househacking a legal multifamily unit is that lender allows you to use the vacated units of 75% market rent as an income to offset the potential current mortgage.

I have been managing this one property where everything has been going well and housemates have been happy and even renewing their lease for the past couple of years with no complaints.

The property owners IN MASS burnt down their properties, which, since they did not file insurance claims was actually the only LEGAL way to free themselves of the continuing negative cash flow of these buildings.  

Will this optimize your tax position or legal position?

I've heard of house hacking cases where the tenants essentially evict an owner with false complaints to the rent board. 

This is not tax or legal advice; engage those professionals.