Good point on Boom Town, I have no idea what I was thinking what I said that. But in pointing out that he should be multi adventure by that logic you're agreeing that Sarah Jane Smith and Jackie Tyler should be as well. (Because you failed to respond to my distinction between adventure and story)
As for River, Scrooge references The Day of the Doctor (novelisation) and The Diary of River Song (audio series) has multiple references to older Doctors, and given the exchange with Ten in Silence we can expect that she'll get to Ten eventually.
Now, right you are to say what happened is what matters. What happened is that there is clear indication that Ten and River have met before, and River expects THIS FACE to know her. There is authorial intent that River and Ten have interacted on at least some of the things she's mentioning in that episode. That is what happened. This isn't speculation, this is what the narrative tells us. Hence the correct term is not "narratively ambiguous". The narrative is not ambiguous. There are other terms you could use. But "narratively ambiguous" is not one of them. The narrative is quite clear on the fact that River and Ten have adventures together.