Yea, I believe Targaryen's who die by fire are not really dragons (but are real Targaryens), I'm pretty sure Dani calls Viserys a false dragon right after he dies. I would think it would be more like Berics resurrection but dramatic effect certainly could be used, just not sure it would make sense. In the book I think right before Dani and Drogon fly out of the arena she is hit with dragon fire and she is not harmed by it.
Yeah - I don't know what the rules are exactly but it seems like there are 'two kinds' of Targaryens. The other key player here though is Melisandre - I think she's looking for redemption after the disaster that was Stannis's battle with House Bolton. I think something surrounding Jon will spark that in her. Does she have some kind of intuition when it comes to King's Blood? I mean, if Jon is a Targaryen, her knowing he has 'King's Blood' would be another kind of cool, dramatic way to reveal his true identity. And Now that I'm thinking about it - Melisandre and Jon have met before....in the show, they have these two conversations:
In the book, they have this exchange, which is even more enlightening....
Melisandre: "This (the Wall) is my place as it is yours,
and soon enough you may have grave need of me. Do not refuse my friendship, Jon. I have seen you in the storm, hard-pressed, with enemies on every side. You have so many enemies. Shall I tell you their names?"
Jon: "I know their names"
Melisandre: "Do not be so certain. It is not foes who curse you to your face that you must fear, but those who smile when you are looking and sharpen their knives when you turn your back. You would do well to keep your wolf close beside you. Ice, I see, and daggers in the dark. Blood frozen red and hard, and naked steel. It was very cold.
Jon: "It is always cold on the Wall."
Melisandre: "You think so?"
Jon: "I know so, my lady."
Melisandre:
"Then you know nothing, Jon Snow"