Recently I had been listening to Bhante @sujato talks on youtube in various things, and he frequently said that later buddhist texts mostly are about buddhists talking to another buddhist.
On contrary EBT have lots of instances when Buddha is speaking to non buddhist. And then he said that he cant find an exception to this (LBT containing non buddhist)
I dont know if this is coincidence or 84000.co has been eavesdropping his talk, in short interval recentlt they had been releasing two minor and obscure sutras in which non buddhist is the interlocutor.
And release a major and popular sutra in which some of the master figure is non buddhist.
1st is Victory of Ultimate Dharma.
In which a non buddhist Rishi with matted hair interrupt a Bodhisattva who want to ask question, and saying that the miraculous display of the Buddha is irrelevant because Narayana and Mahesvara can also do it. And he ask some question related to the beginning of universe, destruction of universe, and the subtle soul.
2nd sutra, Question on Selflessness
In which some Mahayana followers is questioned about the doctrine of no-self, by Tirthika. Variant version tell us that these Tirthikas are Nirganthas (Jain)
3rd sutra, The Gandhavyuha.
Link is unavailable because they made it available only in app for several days.
This popular sutra narrates the journey of Sudhana to meet spiritual teachers, and some of them are clearly non buddhist in appearance. Although, clearly they are Bodhisattva in disguise, and it is not meant to be historically accurate.
I just want to point out the exceptions, though I still think Bhante Sujato argument is still valid. These exceptions are obscure, minor, very few compared to the body of scriptures, and I dont think they are derived from historical events. I think these are mostly teaching tool or just showing how to refute the doctrine of non buddhist