It is unlikely for whatsapp to need root privileges, and impossible for zygote to ask for them. zygote is an essential system component that is started by /init process itself, so it does implicitly inherit root privileges. matter fact, zygote is responsible for starting every other app, being it system app or not.

Having said that, these two apps are strongly malware. if you have adb, issue 'adb shell ps | grep zygote', I believe the output will be two apps: one is the real zygote, and the other 'zygote' is part of a package name.