This is not a cdkey redemption solution but a way to use your currently owned key. Just need to acquire the official GoG installer for warcraft 2.
How to use your old jewel case cdkey or gog key without the gog cdkey changer and not be muted/sent to the void when trying to chat in the battlenet lobby.
1 - Create a new note pad file. I leave mine on the desktop.
2 - Open that and enter the following
REG ADD “HKCU\SOFTWARE\Blizzard Entertainment\Warcraft II BNE” /f /v “bnkey” /t REG_SZ /d YOUR16DIGITCDKEY
3 - replace the YOUR16DIGITCDKEY to your jewelcase / gog cdkey
4 - save, exit and rename it to whatever you like with .bat as the extension instead of filename.txt, example keyfix.bat
5 - double click and run this file after launching battlenet launcher. Before you start Warcraft 2. The bnet launcher updates the key all the time, so if you start the game with the launcher. DO THIS EVERYTIME YOU OPEN THE LAUNCHER, before starting Warcraft 2. You can avoid having to run this file we just made if you don’t use the launcher and open from other places like your war2 directory and Warcraft II.exe
I made this because I was tired of using the registry editor and gogs key changer to change my key after bnet launcher overwrites it.
Way faster and blizzards bnet launcher key has me muted.
With my original jewel case key, I can chat with others.
UPDATE: Uninstalled the battlenet/blizzard launcher version of war2. Restarted computer. Put in gog key and ran gog war2. Closed game. Ran battlenet launcher and opened any other online game through it. Closed that game and checked registry to see if war2 cdkey was changed. It didnt… SUCCESS. Now do I ask for my beer money back or donate my $ in hopes that Blizzard fixes this muted shared cdkey issue. 
If you are looking for other fixes, check out github from FunkyFr3sh.