Hi twinage. What a big question. By dream walking, do you mean waking up in your dream? Effecting your dreams at that point? Just looking around? Whatever your intention, what comes to me is how stones enjoy supporting our physical bodies as we humans sleep. That gives us a feeling of security, which allows us to concentrate on dreaming. One of my favorites is to place a cut amethyst geode on each side of my bed before I sleep. They hold my physical body in wonderful energy as I dream. Another thing I've done is place a crystal at the head of my bed, another at the foot. Then all four! It all felt great. If you have issues sleeping due to stone energy, try different stones, fewer stones, or set them physically farther away from you. Tell the stones their energy is keeping you awake, and they might gentle it for you.
Regarding a crystal to help you dream walk, why not start with the moldavites? You said you didn't feel energy with them. Maybe they are waiting for you to listen to your inner gudiance before they begin to play? Didn't you say you bought three moldavites? So you can have one for the past, one present, one future. One for you as a girl, one for you as a woman, one as an elder. Triple witching, my friend calls it. ;-) The only limits are those we place on ourselves.
Which crystal is best for dream walking? I've done lucid dreaming with everything from ordinary (?) rocks to pristine crystals. They all dream fine. It's up to you to work on waking up in your dreams. If you become excited (very common), you may pop back into your body awake. In that case a calming stone might help. For starters, maybe ask your moldavites to meet you in a dream? That can be a lot of fun. If you feel "yes" from them, watch your dreams for subtle instances of three--the three moldavites. Pay attention to how you feel. That's a reliable way to recognize things in dreams that look different. Be patient with yourself. A lot is going on as we dream, most of which we forget upon awakening.