I've been a CTO/CEO and have hired many people over time. Some of this has already been said, but: 1. Those jobs may still be open, reasonable people wouldn't hold taking another job against you. Work is work, and those who step back into discussion with you will show you a reasonableness that you will value more than before. 2. Situations like this is why sign-ing bonuses were invented. If you're COO of anything, yo…
This might be a derail, but what is the normal procedure by which one negotiates for a signing bonus or a severance package? Some sample verbiage would be nice.
But, the only real answer to this question is to talk to a lawyer. And, don't be afraid to negotiate aggressively. After all, this is your first chance to show your new bosses that you're a tough negotiator. Be fair but never be a pushover.