Hi Owen-
yes, I am trying to use a tour layer that I am hosting as a feature service-- I had thought that was allowed in this story map template (although not in all apparently, which is a bummer as I don't want to consume credits for something I should be able to host)
I am also having trouble saving when I try and change a photo from the 'not available' image that is the default. My FC has one URL field that has the links to the photos but if I try and add or change something, that causes the new changes to fail to save. I was able to get around the adding a new tour point by creating a new point in my FC and republishing. seems anything I want to change after the fact that has to do with adding more information makes the project fail to save.
I can send you a PM with my web map details-- right now its not public as I dont really want to keep broadcasting all my test maps. thanks for the help offer.