I have a C-Corp and sold some vesting stock to non-employees like advisors. Some did an 83b election and others did not. How do I report these grants in both cases?

The 83(b) election allows the recipient of the stock to declare income in the year of the grant to the extent that the fair market value of the stock received exceeds what they paid for it.  As a matter of symmetry the grantor can deduct an offsetting expense.  If the grantees were employees of the C-Corp this would be reported as "wages" on their W-2.  Since the grantees are not employees the appropriate reporting would be 1099-MISC's. 

In the case of the grantees who have not made the 83(b) election their reporting requirements, and yours, will occur at vesting.

Tom Young