The hearth and the Salamander can also mean happiness and if Montag chose to be happy or not. The two things in his life his home and his work. Did it really make him happy. He chose happiness over this home and his work by reading the books.
This picture I think fits Richard Parker, because the quote says "We all have a fighter in us" and obviously he is a predatory animal, but under the circumstances of being stranded in the life boat, he has to fight for his life and continue to stay alive.