I can clarify the child device issue with the new SmartThings Alexa and Google integrations. Currently, only devices with a “main” component are being sent back to Alexa/Google.
Hence, a multi component device with “main” and for example two more components such as “switch 1” and "switch 2 " would only expose the “main” switch. If the “main” component was named “switch 0” it would also not be exposed correctly.
If the main device is spawning of unique child devices with “main” components, that will also work.
Does that help?