How do I find someone for professional advice on this? Someone familiar with startup options and shares for employees. I have questions like: How do my options affect my personal tax situation? Does accepting the buy back change anything? Should I just treat the buy back like capital gain?
Outside of that, call a few tax accountants and interview them. To be fair this isn't that rare or complex of a situation or problem and most tax accountantants will be totally fine. Just avoid places like HR block on the corner as those aren't going to be much help.