I would expect the power grid to fail within less than 100 hours (made up number!) after the humans went poof. This would make many things (gas stations etc) rather hard to use.
I don't know if I could learn enough to clone a human being. The raw amount of effort required would be enormous. It might be quicker than an uplift project.
Multiple universe theories typically are discussed in Philosophy every once in a while. The old thread on
Quantum Immortality describes the basis for my post in this thread.