This is an interesting set of questions. While we expect to talk about flaws because it comes up in many lessons over writing characters, there is less discussed about fear.

My characters definitely have flaws but the fear is something that depends on the story. They probably have fears but if it's not something that comes up in the story, then it's something not mentioned. I wouldn't want to randomly toss in a conversation about fears or something just to have it involved.

All of my characters have some type of flaw because no one is perfect. Even the elf mage type character has flaws. They may go unnoticed by the other elf that is enamored with him, but there are still aspects of the character that can be problematic.

Sometimes, it can even be the flaws that help attract a character. For most, the mama's boy might be considered a problem. However, I have a story where the love interest really likes how close the character is to his mother because he lacks that due to a family that disowns him.

I don't use any particular flaw, on purpose, however. So, it's not like I lean towards one in particular or get more mileage out of anything. Each time it depends on the characters and the story.