It's odd that KE can see the ticket but only its DL segments. With no DL segments, KE wouldn't have been notified of the ticket unless they're doing something like finding it on some universal airplane ticket database rather than in their own computer system.

ARPT must mean airport check in, but verify this with one of the experts here. I hope it doesn't imply some sort of request status.

Good luck getting another carrier's PNR from DL. I find that many agents don't know how to find it and will insist on giving you DL's PNR. [I miss the good old days of PMNW documenting all other PNRs on their PNR for you.]