[annalex]

Here's a related question. St. Justin Martyr wrote dialogue with Trypho, where the same methodological device is used: an opponent is presenting an unbeliever's view and St. Justin responds with the orthodox view.

Now, one may point out that Boso is completely fictional and Trypho could have been an actual opponent. But it does not seem to be a distinction strong enough to condemn the dialog method as "foreign". If you are with me so far, we are left with

As the right order requires us to believe the deep things of Christian faith before we undertake to discuss them by reason; so to my mind it appears a neglect if, after we are established in the faith, we do not seek to understand what we believe. Therefore, since I thus consider myself to hold the faith of our redemption, by the prevenient grace of God, so that, even were I unable in any way to understand what I believe, still nothing could shake my constancy; I desire that you I should discover to me, what, as you know, many besides myself ask

Is this breaking up the faith stage and the reason stage "foreign"?

[Kolokotronis]

“Is this breaking up the faith stage and the reason stage “foreign”?”

We must be talking past one another. There is nothing strange or unOrthodox about a dialog style, whether with a real or a fictitious interlocutor. You've lost me.