Questioning is for when you're figuring out what you're attracted to.
Intersex is more biology, it presents in many forms such as, for example, when a person is born with a vagina and undescended testicles, or has XXY chromosomes. Intersex individuals sometimes don't even know they have a condition if there isn't much being expressed physically.
Pansexual is similar to bisexual but they are attracted to people regardless of gender identity. So say me, for example, I'm bisexual because I primarily am attracted to masculine men and feminine women, generally I'm not as attracted to androgynous looking individuals, trans, feminine men, or butch women. Pansexual people would be.