If I apply 2015 Calif tax refund toward 2016 Calif tax, is refund still reported as Fed income ?

Yes BUT only if you itemized your deductions in 2015. It would not be taxable to the state though. 

If you didn't itemized your deductions in 2015, then you do not have to report it.

You can tell if you itemized deductions by looking at your 2015 return. If you have a Schedule A present, then you itemized your deductions and should enter that refund (probably reported on a Form 1099-G).

thankyou