This LINK might be the basis which a statement from an ARM employee on the official community of ARM.
Question now is if the "latest" Mali drivers will be part of the partnership between MTK and Flash team to be used for the Android N build. Such drivers are part of the proprietary packages required for any build so "exclusivity" has always been a "thing" on any business model.
Same goes to ARM, even if the "latest" Mali drivers indeed covers T720 for Vulkan API on Android N, there's such a "thing" known as conformance that needs to be met. Just like how Google has CTS for manufacturers.