I read them as following:

“I” never said we should kill him.

Someone else said it.

I “never” said we should kill him.

I didn’t say it.

I never “said” we should kill him.

I just thought it.

I never said “we” should kill him.

Someone else ought to.

I never said we “should” kill him.

It’s just a possibility.

I never said we should “kill” him.

What did we do? We could have given him cookies.

I never said we should kill “him”.

Someone else though.