Just water source blocks.
Yes. It's the only way you can get it. I believe you need to have Xbox Live to buy it, because you can not get Minecraft as a retail version, so yes I believe you do need Xbox Live to get Minecraft.
No, you do not need xbox live you only need the points to play minecraft (1600-$20)
no
You need to make an account and then pay for Minecraft and download it.
You need Java.
NO.
Because squid do not have legs to walk, they can only swim, and they do not have lungs to breathe air.
no a squid does not have a shell
You cant. You need to find it.
You need to programme them in. Minecraft uses OpenGL and some Java, so you would need to learn those languages in order to make a mod.
I don't believe you do. I would think that if you wanted to make your game multiplayer then yes, you would then need XBL.
You can buy minecraft at minecraft.net. First you need to make an account, then you need to buy a premium for that account. Then download minecraft, and login. Now you're ready to play.