Dany went into a bath that was deemed too hot. Nothing happened. She touched the dragons eggs after they over hot coals and nothing happened. But her servants hands were burned. So there’s that.

Jon is most likely a Targareyan but not a dragon and fire would kill him. Remember when he saved Lord Commander by throwing a lantern at the wight. Jon burned his hand so that rules that out unfortunately

I was thinking that too and he is most likely is a Targareyan but not a dragon. Because remember in season 1 when Jon saves Lord Commander and throws the lantern on the wight Jon burned his hand.