2) "all about" means inclusively about. In reality you can drop the "all" in most cases and not change the meaning.
3) "extra decibel of joy" this expressing in an music based idiom. Often when people are happy they sing so an "extra decibel of joy" just means they are very happy.
4) "cradle-to-grave" an idiom which means from beginning to end. You will see this used a lot in business record keeping.
I hope this was helpful
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