It is specific.
From XBE -
- When you use the Attack action and attack with a one handed weapon, you can use a bonus action to attack with a hand crossbow you are holding.
A hand crossbow is a one handed weapon. If you attack with a hand crossbow you made an attack with a one handed weapon. Since
"you are holding" the hand crossbow you can attack a second time with it as a bonus action.
No, a hand crossbow is a one handed weapon and counts as a one handed weapon you are holding.
Nothing, it was a separate part of the post.