First and foremost, thank you so much to everyone who had a hand in working on this translation and release. The state of the translation as-is is more than enough for so many of us, and I know I speak for several of us who have been waiting for years when I say this. We're happy to be able to experience this game and story at all, and you've given us that much.
Second, for people having issues with the tailing mission crashing: I remember people having similar issues on fan translated games in the past like .hack//LINK and Valkyria Chronicles 3. There would just be certain common parts of levels or missions or menus that could crash the game, and some of it was needed for story progression. One way around this can be an unmatched iso, you should be able to load your same save file onto the other iso and play past the part that crashes then save and switch back.
The best most surefire way, in my opinion, is to use a physical UMD should you have the means. I specifically hacked my old PSP for this reason, instead of using an emulator on phone or PC, or even hacking the Vita. I would rather play on the Vita or PSTV, but I play on the PSP just so that if I hit a snag or a crash, I can pop in the original UMD disc and guarantee myself getting by and then switch back to my patched iso. I know this isn't ideal for people without a hacked PSP or people who don't want to import the game, but I thought I'd throw it out there for people like me who will, because it works.