Thanks Josh -
So my scenario is the latter - the connection to Oracle is using a database account, not OS authentication. So, that's good news as it simplifies things.
What's interesting is that yes, I can, through ArcMap/Catalog register that connection with the ArcServer instance. After doing this, publishing still fails.
However, I tried registering the same Oracle DB connection file through Server Manager, and it just spins, never resolving in either success or error.
Going through the logs, I see both 001487 error (failed to update the published service with the server-side data location) and 001369 error (failed to create the service) - I'm suspicious now that the 001487 error is simply a symptom of the 0001369 error - if the service was not created, then all attempted processes afterward would fail too.
There are 2 errors in the log that appear to precede the two mentioned above -
SwizzleService failed
DoAfterSDExtraction failed
Have run up against the Swizzle issue before, so I may review that one and start from there.