Happy to tell you that the Echo speaker arrived this morning. Was a bit of a hassle getting it to connect to the WiFi, but once that was sorted I was able to set the Aux Audio to Line In for the WiiM Mini cable connection.
The sound is of course a massive improvement over the tiny JBL speaker. I have the Echo volume on maximum with volume control from the WHA. I'm not using the Echo for any other purpose at this time so I have its microphone off. The audio sync between the Echo and the main speakers seems to be correct.
The screenshot is of the WHA group settings for a local radio station that I initiate using the WiiM remote mic by asking it to Play the Wave, which is does by Alexa on the Pro Plus accessing the RadioApp service which is built-in to Google and Alexa devices here in Australia.
To conclude, the quality of the sound coming from the Echo, which faces our listening position, works excellently with the main speakers which do not, thus providing the desired result of improving the overall sound in the room.
Thanks again to all of the members here who provided their invaluable and advice and assistance in bringing my idea to fruition.
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