As much as we hate to admit a mistake, they may be right. Okay, so you promised your father to name the hero of your third book after him. Name him Alsandair. Name him Alastair. The first step in naming your characters is to know them.
Names make impressions.
That's why you should think long and hard over them. You want your readers to remember your characters' names long after they've finished reading the book. But before you can name your characters, you must know them inside and out. Create a thorough outline on each one. Analyze what motivates them, what makes them who they are.