stranger danger
A hink-pink.
strange change
If it were a Hink-Pink, it could be "a thick brick." Actually, the question is about Hink-Pink according to the original source for the question which is a book for gifted students. The section of the book asks about both hink pink and hinky pinky, and the question is in the hink-pink category on the page.
The hink pink for "improved symbol of the alphabet" is "better letter." It's as simple as that. Next question, please!
Fine Nine.
Odder trouble could be "stranger danger" while hink pink could be "clue glue."
Someone who offers trouble could be a "danger arranger" but since the "f" is right next to the "d" on the keyboard, there is a good chance you meant to ask about "odder trouble." That's stranger danger.
Double trouble is a hink-pink or rhyming word pair for the riddle "two dangers."
little riddle
blue glue
bread spread
A hink-pink.
bag tag
dog log
double trouble
spring thing, summer drummer
big pig