As for other Trek characters traveling back in time along their own timeline
and changing the past to invalidate their own existence and surviving
- are there any other examples? I'll need to do a little research I think!
Hehe, here's some food for thought:
In "The Naked Time", Tormolen died and likely stayed dead even though they went back in time 3 days on their own timeline and altered their future by not reliving what they went through. They still retained their memories and instrument data of coming up with the time travel formula. Since they didn't relive the next 3 days, that should have invalidated discovering the time travel formula since they would have never been forced to use it to restart the engines.