"  "...please contact us so we can make arrangements..., etc."  

I handle everything myself by doing my own title searches, write up my own deeds, and arrange meeting with a notary, pay with cashiers check, go to courthouse and record everything.Why pay $15k down for something to create a mortgage payment when I can pay $15k all in and rent the house out for $600/month for the rest of eternity. 

The national group has a special appliance deal arrangement with The Home Depot with everyday very low pricing on select appliances that can be accessed via your membership with the local group. 

Keep on top of the PM for awhile to make sure he is doing all the things you need, i.e. registering the property with the City of GR, arranging for the inspection, having any work done in compliance with EPA RRP rules, following fair housing laws, using forms that are actually legal in Michigan, etc. 

If so, what are the possible arrangements for splitting the profit?

I've got to wonder what unmentioned and unposted arrangements you had with said borrower?

@Patrick Scifres  one thing your making the assumption that the seller ( wholesaler)  fully understood what a buyers broker arrangement is. 

@Hillary Windrem, it does not sound like a fair arrangement.

Just make sure they know immediately that they will have to make other arrangements due to the house being sold.

Not to mention, the Mortgagee's likely violation of their financing arrangements.