Is there a method to freeze and thaw an application vs uninstall/reinstall? On a non-rooted Android 5.1 phone, is there a way to "freeze" an applications, settings, and data? 

I don't want to uninstall or need to consistently kill a process. I would like to archive an application, and when I need it, take a brief moment to "thaw" it, use it, and freeze again when done.
You shoud try a software developped by gatesjunior, a Recognized Developer at XDA-Developers. I doesn't require root for hiding/blocking apps. 


Download debloater.exe here (mirror) for Windows (May require .Net Framework 3.5 or higher). Download dmg file for OSX here
Enable USB debugging on the phone
Connect the phone to the computer (Should install drivers to get the phone detected)
Run debloater, clikc on "Click here togin"- should list all installed apps. Just check the check-mark related to the apps you want to hide/disable then click the first icon in the top left.




I found the complete link on how to use the software, check it out here