Two things I learned since yesterday. The GIMP filter I used was Animation > Waves, not Animation > Rippling. It just looked like water ripples to me.
The other thing, which was helpful in combining the elements, was the Animation > Blend filter. At least two layers and the background are needed. There doesn't seem to be a limit to that number. Running the filter will output the required number of frames in the transitions.
The banner has been redone in the same way.