If you don't yet have the property under contract, you could be doing a lot of work with no guarantee of getting the house, so I wouldn't advertise until I had the property under some sort of contract. At the very least, get an option contract signed and have the option stipulate the terms of the sale via AFS. Also stipulate in the option that it is assignable and that you are able to advertise for a tenant or buyer and have reasonable access to show the property before you exercise the option. Register the option on title so they can't sell from under you. Then you can start advertising the property.
You may even find a buyer rather than an RTO tenant. Then you could make a profit without the RTO work. Let's say you agreed to buy the property for $300k, but you find a buyer willing to pay $315k. You will have made a quick $15k (less legal fees and marketing costs). This could be done via assignment and a direction to pay or via a simultaneous close, depending on the situation (ask your lawyer). As long as everyone knows you will be taking a small profit for your services to facilitate, it should go smoothly. Please keep RECA rules in mind - you don't want to be viewed as 'transacting' in real estate if you are not a realtor.
