Do you believe that other universes exist with different beings?

I agree with most of what you're saying, but I think you're throwing around the word "universes" too lightly. As far as I know, the idea that black holes lead to more universes is still science fiction. It hasn't even been shown yet that black holes lead to other places in [i]our[/i] universe. "Universe" means you can get to anywhere within it from anywhere within it (very theoretically, given enough time). Even though a star may be thousands of light years away, it's still in our universe because we could get there if we could live and fly a space ship for billions of years. Another universe is somewhere you can't get to by ordinary means from this universe. No matter how far you traveled. For example, Narnia, if it exists, is in another universe, because you need magic to get there. I think there's a scientific consensus that there is only one universe, and it is infinite. Our universe has no geographical "end".

But yes, your logic is spot on. I believe it's highly unlikely that there is not intelligent life on other moons/planets in other solar systems and other galaxies. We are not the only ones out there.