It frustrating, tag swap issues can one of the hardest issues to resolve until after every thing is sent to corporate at the 5 day mark but it sounds like from the description you have a a double tag swap since your tag was placed on a third persons bag. The bag type looks 100% correct.
I think the agent was correct in saying that a WorldTracer file would not be created initially if your route didn't include another carrier but they can be created manually and I thought they would have been opened automatically at the 24 hour mark, this could have changed or I may not remember this correctly. I honestly don't remember how to push this manually. Remember that the purpose of WorldTracer is to create a match so they wouldn't want to create a WorldTracer file after a match is created, that would be a waste of resources. Unfortunately WT will not let anyone beyond airline agents search trace for security reasons.