I have enough money for the down payment but I need help carrying the loan.

It would take probably $50k-80k to get the home to a condition that it may sell in the high $300's - maybe - not at all worth that high of risk in my opinion. 

There are usually a lot of attorneys and title companies involved in wholesaling....I don't think all those professionals would risk their credentials if what they were participating in was illegal.Like everyone said, look up your local laws as they are different in all 50 states but as long as you are following the language in the contract the seller has signed you should be fine.If it says don't market, don't market, if it says no assignment, don't assign...if that's the case, get a new contract.

I’ve considered the risks in this route.

In your case, I think $200 is reasonable because they obviously care for the property  as if it were their own and you could avoid a costly vacancy or the risk of a lesser tenant. 

How big of a risk am I taking? 

It isn't prosecuted against often so there is low risk as the wholesaler but if an issue arises, the listing agent could report what your agent was attempting to do and they could be in trouble with the state board.This is why most wholesalers write their own contracts, do their own marketing, and work with off market leads.WORD OF ADVICE: No many investors are going to buy a property from a wholesaler that is on the open market.

My sense is there's a reason for that.I'd be a bit concerned that some type of failure could result in water damage, in addition to the risks that you mentioned. 

@Daniel M Gibson sticking to fundamentals and your "gut" is always the best course.Unlike 99% of the investors on this site, my take is that investing for cash flow is a bad idea...it creates a jaundiced view of how things work...meaning that investing is about controlling assets as wisely as possible...not immediate cash flow.I use seller carried loans routinely because I'm in for the long haul (and I don't need rental income to survive)...as long as the purchase price makes sense, I could care less about income...the concept is debt paydown and future equity.

Why take the risk if you don't have to.