Mysterious felix the cat theme.

The uploader sourced this song, and the others on their channel, from the now dead Felix the Cat website. It was on there as early as 2001 under the same vague "Felix Live Action Theme" name, and was also cut off at 40 seconds.
You could try to contact Don Oriolo, as this would have been made during his prime of the franchise. He might not know anymore, however. It's been a good long time.

I have a couple theories about this one, though. It could be...

• Opening / credits theme to "Felix the Cat Live", a show from the 70s. The uploads on YouTube have different credits than what would have been presented originally. But it's too early in the timeline.
  
• Some promotional song for the Felix the Cat Movie. Unlikely.
  
• An early theme for the 90s syndicated version of the Trans-Lux Felixes (before Mark Mothersbaugh wrote a new theme in '91)
  
• Something from the Asian market, or for Baby Felix.
• Or, it could have just been something Don did himself. He did preform the Twisted Tales intro.