Hello.
I just tried to simulate the behavior of the scheduler, were it to have continued training after 40 epochs. I think I set the initial LR to a value similar to the final ones of the scheduler, and I did not include a warm-up since I only wanted it to decrease. This is in no way a robust solution, it was just a though to approximate what it would do.
The other questions you ask are very task-specific. Even if my loss curve showed signs that it can get better after the 2nd training ended, this does not mean yours would behave similarly. Good luck with your project!