It might be possible with a little work. I'm happy to do it but I'll need to know what rom or build number you're on. Thanks too! I don't see a lot of light colored themes. I've been wanting it on the s4 but I'll try to get it working for the note3 before.
So..
Rom?
Current note 3 build?
That doesn't sound right.
If you've reset or tried wiping caches in recovery then I would assume an app is interfering with the lockscreen. Any lockscreen apps or other mods?
Hmm. Not having the device makes it tough but there should be no lag. I'm sorry I don't have an answer for you.
The only things to try,
-Fresh install or
-wipe caches in recovery
-select lockscreen style in settings
Those are just in hopes it'll clean up whatever is effecting that.