This kind of listing is considered the least ethical of listings (it doesn't really do a very thorough job of serving your client) ... which is why you may see a lot of real estate agents saying all sorts of negative things about wholesaling.This doesn't mean you can't do both ... but you will have to be sure that your broker is on board.

I still believe that if done properly and ethically, this can benefit both the homeowner and the investor, but the agreement has to be fully understood by both parties. 

Ethically, as far as I'm aware, I would just need to make sure the transactions and provided services are at arm's length and I'm not taking any special interest in my clients on the accounting side.

These are professionals with additional training and a stricter code of ethics.

Is there an honest and ethical workaround?

I consider making an onsite visit a critical portion of this- get to know the provider, the neighborhoods, their rehabs and their ethics for operating.

You just have to do what you feel is right ethically and make sure your attorney agrees. 

Not sure if this is what you were wanting, but this is the best and ethical way to handle flooded areas. 

I am particularly interested in a GC with excellent communication skills and work ethic.

As Sharon points out, the listing agent is required to always put the seller's best interests first (within some legal and ethical boundaries, of course), and while that isn't necessarily a zero-sum proposition it almost certainly will come at some expense to you.Get yourself someone experienced to walk you through this deal, if it is a deal at all.