These apps (Stky, Lala, and GameKeeper) store their user data on your device. The data you create stay on your phone. If you back up your phone to your computer or the cloud, that data will be backed up as well.
One partial exception: If you accept Reminders access in Stky, it will sync its data with Apple's Reminders app: reminders from Reminders will appear in Stky, and changes or additions made in Stky will sync back to Reminders. This allows you to keep your tasks in sync across devices without any explicit data storage from Stky.
All apps use a small number of third-party services for analytics and crash-reporting purposes. That means they anonymously track your behavior so I can learn more about how people use the apps. To the extent I can easily do so in a given service, I avoid collecting the actual content you generate in those apps. This behavioral data will be used to better understand, in aggregate, how people are using the apps.