Don't mine the redstone yet as it doesn't drop anything.
Lava has no use right now because there are no buckets. In fact lava is very dangerous in PE as it can set your entire world on fire due to a glitch. I would think a lot of seeds don't have a lava source in them.
Once buckets are placed into the game, making a swimming pool will be easy.
Every time you see an animal in the ocean kill it. They will respawn later, hopefully on land. (I had to kill almost all my animals, but now have lots spawned on land.)