Does a C Corp with no revenue or expenses need to file (still in fundraising mode for the startup)?

Yes, if you have been assigned an Employer Identification Number (EIN) by the IRS, you are required to file a tax return, even if you have no activity. If you fail to file, the IRS will send you a reminder.

If you have no EIN, you may delay filing a tax return until 1) you have an EIN or 2) you have activity to report.

Is there a penalty for filing a Form 1120 late with no revenues and no expenses.