Every last one of those is strictly nickname for me.
Chris,
Brad, and
Gwen work the most as FNs, but I still don't like it.
I never thought of
Poppy as a NN. Hmmm....
I dislike nicknames as names, and nicknames in general. The only instance I'd accept a NN is if the first name was truly horrendous. Other than that, simply shortening a name because you can't be bothered to say three syllables... I don't like that.
Alexander is always
Alexander to me. If a name is already short, like mine (
Blair), and you insist on calling me "B"... we can't be friends, lol.
Mind, I'm only thinking of nicknames as the shortening of a first name; that is rarely acceptable to me. However, a friendly nickname given to you based on a particular event or quality is fine by me. That's personal. Shortening a name is just easy.