All three of those
When I say “kid” to my kiddo i think of Indiana Jones and ShortRound 🥰
If speaking about them to those that don't know me/ them well I will say "My Son/ daughter" To them, it's their real full name or nickname
By his name or I say mate which is slang for friend in the uk
@Sam interesting.
Buddy
@Jen aww that's a cute one.
When speaking to them? Their name. When speaking about them? Usually “my kiddo”