In Fedora, is it possible that removing the kernel-modules-extra package caused corruption of btrfs superblocks (and maybe other parts too) in a luks encrypted partition?

No, if you deleted the btrfs driver it would simply fail to mount due to the missing driver, if it's a separate module in the first place. Same with LUKS, if you don't have the tools or the drivers installed for it, it'll just not mount it. You'd have to be accessing the drive directly with something like dd to corrupt it.