In the UK, which is the intended audience for these boards "Super-WiFi" is more often a part of the "Broadband Pro" packages. If you are using a supplied WiFi extender then your first action should probably be to customer services to see if you can get a further extender. Thanks to some fuzzy wording from Vodafone, it's not really clear if these are dumb extenders (seems likely) or form a mesh system. But as you've alluded to, it appears to be a closed system with provisioning and configuration being performed remotely by customer services. You can certainly still add your own additional wired Access Points (APs) likely with very few issues. Adding further WiFi extenders though is likely to degrade WiFi performance, with each one possibly reducing the maximum available speed by half! Regards cloning the SSID of the router into your WiFi extenders, while it makes for a simpler user experience, your WiFi clients will tend to doggedly stick to the source they first connect to, rather than roaming. The result of these sticky connections is that direct client WiFi performance drops as connections are maintained over long distances, and the overall performance drops because of the WiFi transmitters within your own network interfering with each other. So if it's not a mesh, personally I'd use separate SSIDs.
For the record, by adding an extra WiFi-based security cam I recently managed to take my 2.4GHz WiFi to breaking point. The solution has been to bring a long-retired TP-WPA7510 powerline to WiFi AP back online. Using the powerline ability it's located some distance from the router and is set up only on the 2.4GHz band, with it's own SSID just for the cams. I'll move more smarts to it, if and when I detect problems. But at the moment this seems to be working, the problem here having been congestion and not range!
