Question

If you ever read how to kill a mockingbird

Answer 1

Not sure if I’m right but: Euphemism is to say one thing in terms of another in a nicer way.
So 1 is idiom because it is not a euphemism.
Oxymorons are two contradicting ideas used in conjunction, so 2 is allusion.
Simile uses like or as, so 3 is a metaphor
I don’t think 4 is a euphemism but I don’t know what malapropism is.

Hope this helped! :)

Answer 2

Euphemism that’s a right answer