Welcome to the forum :flower:
Sorry no one has offered help until now, I'm not into blu-ray backups however I will try to answer your questions...
1...On multiple titles ...Unfortunately the "Blu- ray Copy" doesn't have "Customize" or "Merge modes that allows this. (AFAIK)
2...As far as looping not sure Fab as a setting for lop or not loop.
3...ImgBurn is more superior then the VSO burn engine provided by DVDFab, use the guide below on how to set DVDFab to use ImgBurn as the default burn engine.