Technically you dont need root to flash gapps. The bootloader just has to allow you to flash it. The "normal" bootloaders do signature verification of the "update" and reject it if not signed by the manufacturer, while the alternative bootloaders typically installed when rooting your phone don't check the signature at all. It's possible for Huawei to allow their signature as well as the one/s used on gapps packages.
I doubt Google would actively block gapps being used on a Huawei.
I doubt Google would actively block gapps being used on a Huawei.






