iCloud tasks do sync with Gmail
This won't work at the moment. Problem is that Google doesn't expose the tasks calendar in their sync procedure since many years, neither over Exchange nor CalDAV. You can only sync tasks into Google's cloud by using an app which directly communicates with Google Tasks (i.e. gTasks for iOS, GTasks for Android). This is the only way to sync Google Tasks over different devices &amp; systems.

Furthermore, iCloud tasks can only be synced between the Mac &amp; iOS versions of the Reminders.app at the moment so there is no other app which is able to communicate with these tasks. Therefore, it's not possible to get your tasks out of the Reminders.app, including syncing it to another service.

For now you would need to decide on one service and stick to it on all your devices. And this would be Google Tasks because you can't access iCloud reminders from Android.

But: in the future, it should be possible to sync iCloud reminders down to Android with SmoothSync for Cloud Calendar which says "iCloud reminders are not synced yet" in the current release notes.