We don't know how to "condition" an AI to respect the well being and freedom of humanity. It's an extremely complicated problem with no simple solutions. Making an AI that wants to destroy humanity, however, is quite straightforward. Guess which one will most likely be built first?

Building multiple AIs doesn't solve anything. They can just as easily cooperate to destroy humanity as to help it.

Uploading humans won't be possible until we can already simulate intelligence in computers. We can't have uploads before AI.