There are many tools such as Modloader and minecraft Forge that allow different mods work together.
Yes
No, you can't take one item from a Minecraft mod unless there is a separate mod which contains that one item.
One example of a superhero mod in Minecraft is Superheros Unlimited for version 1.6.4.
Mod Loader is the only mod that will allow your client to run more than one mod at once. It is very safe!
You can, but you need the mod modloader. It allows you to run multiple mods at the same time.
It probably won't work and you'd have to get rid of the mod and try and find a more updated one. It probably will work though.
It will be but not yet it takes much time to make a mod and one with a new world like aether more
I would suggest the Treecapitator or Timber mod.
There are heaps of more ores mods for Minecraft, so I'm not sure if the one you're using will be compatible. All I can suggest is trying it yourself.
The hexxit mod is free. It is actually one of the better and safer mods out there.
we obtain silver from underground in places such as Italy and Greece
There isn't one. Wolves are already in Minecraft. There are other tools and mods that can help you find and tame one though.