Well, double meaning usually means a pun, at least to my mind. A better definition in this case would be 'metaphor', I suspect. Life and hound are said to have certain things in common. Or, since he used the word 'equivocal', have uncertainty in common. Life, like a dog, sometimes comes in a friendly fashion, but sometimes attacks.
Tone is slippery, so you can support lots of answers, whichever appeals to you personally. Same with diction. Make your own case, from the examples below:
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www.poeticbyway.com]>
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www.poeticbyway.com]>
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