With android kitkat (in my Moto g1), i could share my wi-fi via mobile hotspot. After upgrading to lollipop, turning on hotspot would turn off the Wi-fi which i thought was a bug. Now to my surprise, it is happening in my new Moto G4 plus (marshmallow). If this is a feature, then i do not understand why it behaves like that. Is there a way i can share my wi-fi via mobile hotspot ? Sharing the 3G data does not make any sense to me.
The device has to support 2 WiFi frequencies, and the OS has to implement the feature (e.g. Huawei D2 and Samsung S7/Edge), or else you will only get either WiFi in or WiFi out. I've never seen any mention of the original G supporting the feature either, and since I've owned an original G myself, I can say that it can't do it in my experience.
The only way that was able to do it on non-OS-level was FQRouter2, but it's now obsolete and might not work.