kotaKat parent
The default phone and SMS messaging application on all Tier 1 Android OEMs is required to be Google Phone and Google Messages. Also as such, Google stopped maintaining AOSP Dialer and AOSP Messages.
I use a Samsung phone and it has Samsung’s phone and SMS apps.
I use stock Android, and all of the apps I am using are from F-Droid, I do not use Google's apps. I have them uninstalled.
Many of the apps I am using (Gallery, Dialer, Contacts, Camera) are from https://simplemobiletools.com. Source code: https://github.com/SimpleMobileTools. Its Gallery looks similar to Fossify's. Its "About" seems almost identical, so I dunno.
You might want to check the permissions and such on the latest versions of those apps. Fossify is a fork of SimpleMobileTools but without the ads and trackers added by the new owners.