Android Oreo launched a few weeks ago, and with Google releasing a vague statement on the plan for updates for devices outside its Nexus and Pixel lines, it's time we had a look at the plans of other OEMs. Hop in to know if your device will be receiving the Oreo update.
https://www.notebookcheck.net/The-comprehensive-Android-Oreo-device-update-list.244820.0.html
You missed Moto M, the unneeded, expensive, and forgotten child. I know it's not sold in every country but you listed E and C, so might as well insert that to complete the Mediatek circle.
Conclusion: Stay away from Mediatek phone if you're buying Moto brand.