Yes
Yes it does.
There are only non-aggressive mobs when you are on peaceful.
Yes, it is under "Materials" in the Creative Mode inventory.
If the difficulty isn't set to peaceful, mobs will spawn in creative mode.
This isn't easy but you might have to find an abandoned mineshaft or a stronghold and destroy cobwebs.
Peaceful mode is still in Minecraft. To activate it, select Options in the pause menu and change the Difficulty to Peaceful. Monsters don't appear in Peaceful mode. You can't use Peaceful difficulty if your world is in Hardcore mode.
Yes
Yes it does.
There are only non-aggressive mobs when you are on peaceful.
You probably have it on Peaceful Mode thats the only reason I can think of.
Yes, wolves spawn even on peaceful mode.
Yes, it is under "Materials" in the Creative Mode inventory.
If the difficulty isn't set to peaceful, mobs will spawn in creative mode.
Peaceful mode means that no monsters spawn, so there will be no Slimes.
You may have your difficulty set to Peaceful. Monsters will not spawn in Peaceful mode.
No, and why would you need it?