Oh, It seems like you're done with modding this game so ignore all below this.
I played using the newest version without changing anything, and it only froze twice. When I was playing with the newest version before I re-downloaded it, it froze around 10 times. I then customized a few people and got into many games with no problem but before I joined someone who was high rank it froze. I wasn't going to give up so I restarted the game and played more games until I came across another high rank and it froze again. It looks like (I highly doubt this) high ranks cause the freezing problem...? That or some unknown reason or I'm just dumb. All I'm saying is that the freezing problem was half-solved by re-downloading the newest save and changing only things on characters I play as the most.
If you could find out what causes the freezing could you let me know? I'm going to try to save the game first every time I play like you suggest I do and hope that it don't freeze.
Also, the third time I loaded the save the options changed from:
Captions - On to Captions - Off
Voice - English to Voice - Japanese
Vibration - On to Vibration - Off
I hope this helps to determine the cause.