It seems to me that JW's do not believe in the existence of alien beings as the Bible has nothing to say on the matter. Everything seems to revolve around the planet earth and the possibility of there being alien life is considered to be apostate. Sounds a bit like the oppression that Galileo received from the Catholic church when he suggested that the earth moved around the sun and not vice-versa!
If the theory of creation is correct, then it could be that Jehovah has given us up as a bad job or is simply waiting to see how we deal with the mess we have made. Meanwhile, he might have created another civilisation of humans in another galaxy that have not rejected him and are still perfect. After all, why did he create such a vast universe? We can't even see most of it, even with the array of technology we have developed.
It would be ironic if the JW's are striving to be saved when all the attention is being directed to a "better" society elsewhere. There could be hundreds, thousands or millions of other experiments going on. He is the all-powerful after all. It would be stupid to believe that we are the only ones, unless of course there is no truth behind any of the WT's teachings!