A fictitious person's executives and directors are typically real. Or, if fictitious as well, go down the rabbit hole of said contractors until you finally find the real ones.

In the country I'm from, each exec gets a partial sentence in accordance with their contribution to the criminal act. And no, the total amount on years in prison needn't match the total, there's a minimum and also percentages always exceed 100%.

Limited liability doesn't and shouldn't protect criminals from imprisonment.