Corrected w-2 received after I filed an extension for only one state (out of 3). Action now?

I received a W-2C after filing for an extension (and after April 15). The only correction is that my Connecticut (CT) state wages are now much lower than what was originally reported. The original W-2 reported Federal wages (unchanged), NY (unch), NC (unch), and CT (now corrected).

• I filed an extension (waiting on a K-1 in Sep.) so I haven't filed yet.
• I already paid CT taxes based on the orig W-2 and am owed a refund for federal, NY and NC.

My questions:

1. What do I do with the W-2C now? Do I amend CT now or just use the corrected numbers when I file later? Bonus if you know how to update CT wages without filing yet—I’ve had trouble finding the right place.
2. Is it safe to assume I’ll get a CT refund since I overpaid?
3. Will there be any penalties or issues? 

Thanks in advance for any insights!