
Strangely enough I could not reproduce the crash upon ending the turn in the autosaveendturn you provided. Every single time the game would correctly proceed to the "game over" event , no clue what could be causing the crash for now but I'll keep trying and provide a bugfix once I discovered the issue.
*edit* during the 5th or so try the game actually crashed with the bug you reported, will see into it
Considering your questions:
1. no, there is no way to check for the opposite alliance factions morale or collapse points. You have to ascertain their status by the events that are occurring. I tried to implement a resource panel showing the enemy's resources if enough INTEL was gathered but failed to get it working.
2. in singleplayer vs CP AI the Entente convoys are not always attacked by real submarine units but rather these attacks are conducted by "ghost units" using an internal script to work around the deficient naval AI. The may sound cheap but is the only way to put some pressure on the Entente player as the AI is rather inept of efficiently using submarines against convoys.