There is a plugin called World Guard that can do both. Look at related links for its download page.
Yes you can. You could also spawn them in using the spawn eggs.
they randomly spawn all over.
You can find eggs, those can spawn a chicken but not all eggs do, or load new chunks and they will spawn, just not where you want
Endermen spawn in caves or at night like other mobs. They are also the natural inhabitants of The End.
If your on PC their are a couple mods out that can let you spawn him in the game. If your playing on Console this is not possible. Its up for you to find him. ;)
Are u asking how to spawn witches? (well you go into creative and you look for a spawn egg and you will find a witch spawn egg) or are u asking how do they spawn? (Well they spawn at night) I hoped that helped! ~Magpie
You have to download the mod from minecraft to get the lucky blocks. Then the lucky blocks will spawn randomly across the surface.
There are no dogs in Minecraft, although there are wolves. Wolves are found usually in planes or forests. They spawn on grass and dirt.
Try looking in a plains biome, that's where they spawn the most.
Yes, I tend to find diamonds near redstone
Explore around. passive Mobs can spawn almost anywere on land.
There are no seeds to spawn in the ender realm but there are definatly a few where you spawn near a stronghold but they arent easy to find on the internet because of the 1.2.3 seed change and its is unlikely you will find one by luck.