When I uninstall updates of system apps is it persistent? I don't want some apps updated (especially some of built-in apps). If I uninstall updates in settings is it for good or only to next phone restart? 
(I want to have auto updating in google play enabled)

Thanks a lot for answering.
You can enable auto update from Google Play Settings section. To prevent auto update of a particular app, Go to that app page in play store &amp; click the Options Menu on top right &amp; uncheck "Auto-Update"