Contacts are mysteriously disappearing from Moto G (1st gen)
I have the same issue with my Moto G (1st gen.). with just one google account, and FB, Twitter, LinkedIn, etc accounts, all my contacts suddenly disappear and the contact and other apps were really slow.
I resolved my problem completely, the solution was uninstall the Linkedin app, it was artificially multiplying my contacts in other apps and causing slowness and that the contacts did not show in other apps.