Starkiller being alive?
Honestly I believe that Starkiller was just presumed dead. vader lied to Palpatine and told him that hes dead. But then after the emperor wasnt looking, he had took starkiller to kamino to make clones of him, but Starkiller woke up suddenly and broke out. Though vader did make some clones that went mad. I mean seriously, Starkiller is too powerful for them to just claim him as dead. And in the dark side ending when the dark clone sees the body of starkiller/ The body he sees is of a clone. Thats my opinion.