However @Richard Balsam is correct about insurance and everything, getting the rent that is due is a great return, getting them to pay for everything else might be possible but will make everything much harder.

We turned our first home into a rental and the property has around 200k in equity and the return is 9%. 

If so it might be worth trying to find an equity partner who would be OK with a preferred equity return on their down payment. 

Your calculations look pretty good, if you are comfortable with the return you should be alright

If I treat the 401k money as if it were cash, that is a 16% return.

A 30-50% cash return is pretty attractive to some people.

I am a relatively new investor who purchased my first 3 deals (SFR's) here in Lufkin, Texas with excellent cash on cash returns thus far.  

Can you explain what BREIT's "promote fee via up preferred return and waterfall" means? 

Do you know what percentage he was returning on those initial flips by chance?

The wholesaler has found a buyer and is now refusing to return any portion of the assignment fee.