Lip Sync New Video to Existing Audio.

I have an audio track of my brother singing, and a 720P still image of him as a cartoon.

I would like to generate video which animates the image and lip syncs the cartoon with the existing audio.

I initially got this warning

But eventually got the process started with this prompt:

Sync the audio reference to the first frame reference image.  Animate the reference image to be playing the guitar, and lip sync the guitar player singing the song. . Maintain the original zoom ratio throughout. The audio to be unchanged. The facial expressions to match the lyrics of the song.

Unfortunately Firefly generated new audio, although it did a lovely job of syncing it to the visuals.

I used Seedance 2.0

The above 720P sized image as the First Image.

A 343Kb mp3 of the first 15 seconds of the song.

I have attached the resulting mp4.

Is it possible to do what I describe above?

Is there a secret to laying out the prompt?