Other religions focus on that Isaiah 65:25 is talking about a spiritual, heavenly paradise. The WTS has argued in the past that it has to be real since when will a lion ever be in heaven. Here is a quote from just seven years ago showing that they still believe in a literal, earthly fulfillment.
*** w00 4/15 p. 17 The New World—Will You Be There? ***
While you are thinking about what you may enjoy in the new world, picture the scene that God’s prophetic word sets out: "‘The wolf and the lamb themselves will feed as one, and the lion will eat straw just like the bull; and as for the serpent, his food will be dust. They will do no harm nor cause any ruin in all my holy mountain,’ Jehovah has said." (Isaiah 65:25) Human artists have tried to paint that scene, but this is no mere word picture produced with artistic license. This will be real. Peace will prevail among humans and will be matched by peace with the animals
*** w59 8/15 p. 498 Be Ready Always to Make a Defense ***
Often people object when you are describing the peaceful and righteous conditions of the new earth, saying that paradise is in heaven and there will never be such conditions here on earth. How can you convince such people that your hope for a paradise earth is sound Bible teaching? For instance, you can illustrate it with Isaiah 65:21, 22, where it states about the new earth that they will build houses and inhabit them, they will plant vineyards and eat the fruit thereof. Isaiah is surely not speaking here of a building and planting program in heaven; he is describing peaceful and righteous conditions here on earth. Furthermore, verse 25 says: "The wolf and the lamb themselves will feed as one, and the lion will eat straw just like the bull." This prophecy can apply only to the earth. No one would want to maintain that one day lions will eat straw in heaven.