Thanks for the replies, especially for the link to a former post from 2016. It's almost exactly what I'm going through, except mine is a paid ticket and not an award.

I'll post updates as I go to hopefully help others in the future. With DL's pending joint venture with KE this certainly needs to be more streamlined. Here's where I stand:

I sent Delta Twitter a DM asking for the 8 character KE confirmation code. They replied back overnight that there was no such thing as an 8 character code, but they DID have a 6 character KE confirmation code. When I entered that code into the KE website I received an error message that stated that they were restricted and not able to display the reservation online. (This was different than entering my DL info into KE where I got a no reservation found error).

I created a KE SkyPass account to utilize their chat function. Once chatting with a KE agent I provided my DL ticket number, 6 character KE code, and passenger names. They immediately were able to provide the 8 character code (which is all numerical). When I entered the code into the website, I received the same error that they were restricted and could not display the reservation online.

On my second chat with KE, the agent stated that because it was a codeshare the reservation would not display online because they are "limited" because it is a DL ticket. Also, advance seat selection is not allowed when the flight is a DL codeshare. So while my issue is still not totally resolved, it does give me some comfort knowing that KE sees us in their system for the two segments (ICN-BKK and BKK-ICN).

That's all the time I've had to work on it so far. The trip isn't until October, so I'm not in huge rush. When I have time I plan to call DL and discuss with them, and then call KE and confirm the KE segments with them as well. Had to hop on a redeye to SEA last night, so that's it for now. If anyone else has any experience with this any input is welcome!