No. The key feature of historical fiction is the addition of fictional elements. While it should be somewhat true to the historical period, it can deviate in many ways. Authors may create fictional sub - plots, change the sequence of events slightly, or even give fictional motives to historical characters. This is all part of the creative license that comes with writing historical fiction. But at the same time, it should still give readers a sense of the historical context.
Not always. Historical fiction is a blend of fact and fiction. Some elements might be exaggerated or altered for dramatic effect. For instance, an author might make a battle seem more heroic or a character's role more prominent than it actually was in history. But that doesn't mean it's completely untrue to history. There is usually a core of historical accuracy that the fictional elements are built around.