If the rebels had complied and obeyed the law, the planet would not have been destroyed.
That's not how this works. If the rebels break the law and the empire punishes Alderaan, that is so-called "collective punishment" - punishing someone who has not committed the crime for someone else's crime. Under pretty much every body of international law hereabouts, this is forbidden. It's like if I punched you in the face because someone somewhere jaywalked. Neither fair, nor legal. Now, of course, one could argue that under imperial law, it would be legal, but that would mean to just bend over and believe that every whim of the emperor's is legal and then the empire could do no harm because it would simply always declare itself blameless and in the right. (Nazi Germany did just that, which is why we have human rights now around here btw.) So if we go by international law or just a general sense of justice, then self defense against the rebellion could potentially be justified, but "self defense" against the children of Alderaan is just bullshit, that's just not an argument, that is the kind of excuse that every bully ranging from domestic abusers to actual dictators like to use - be it "look at what you made me do, little kid - you made me beat you because you broke some arbitrary rule I just made up, this is all your fault" or bombing civilians under the pretense of defending the own country from some nebulous weapons of mass destruction or other fake flimsy pretenses.
Just like any "punishment" against the civilians of Alderaan for something they did not do is not an argument that will get anybody anywhere. It's just collective punishment: hardcore war-crimey. No way around that.
Was every cleaner, cook, clerk and technician (and their families) working inside the death star the rebels blew up a criminal?
A criminal? No, but the rebellion did not blow up the death star as punishment for e.g. Alderaan. The death star was blown up in self defense against a current attack. Would any lesser means have been sufficient to end this attack? I cannot think of anything that would have dissuaded the death star, so the attacking military installation death star had to be destroyed to end this attack. Allowing the argument that nothing any opponents of the empire do can ever be legal because the empire makes the laws would just mean rolling over in front of injustice which is not acceptable in the face of absolute totalitarian arbitrary despotism. If one were to seriously consider that line of reasoning, then any and all military actions against Nazi Germany were crimes. I will not entertain such lines of thought. Unlike Alderaan, the death star had already fired up its planet-killing lasers and just turned out to pull the short straw in this fight its commanders started.