Welcome to the forum.
Just some thoughts:
WMV is CPU intensive to both decode and encode. The time is probably the way that it is, and might well be dependent on your computer. There is a LOT of compression going on.
Now, with regards to the Audio, there have been users, who had issues (not unlike yours, but not identical) with Export, when they had Clips on the fixed Narration and Soundtrack Audio Tracks. In many cases, just moving all of those Clips to a regular Audio Tracks, has cleared up many/most of the issues. That would be the first test that I would run - just lasso them, and move them to another, free Audio Track. Test.
I believe you are exporting in HD 720P
Click on Advanced--> Audio--> Change the Bitrate mode to constant.
If this does not solve your problem Change the Encoding Passes to "One" in the same tab
Thanks so much. I'll try a mini test with multiple audio tracks and see what happens
Thanks for the input, I'll run a test and see what happens
Sorry for the delay in writing back. Your recommendation worked out perfectly. Thank you