If keeping this person onboard requires the effort of training them and keeping their comp a secret, it's not worth it. It will get out that this person is gett

If keeping this person onboard requires the effort of training them and keeping their comp a secret, it's not worth it. It will get out that this person is getting paid senior comp for entry-level work, and that isn't going to fly for the people who are performing. Don't overthink this. They're not fit for the role, and to boot, they misrepresented themselves. Your process screwed up, but the key is to not compound that. I'd encourage you to still be decent and give a good severance, because this is ultimately your company's fuck up, and you should take your medicine.