To close out this thread - the RaSCSI came in, and while using it, all my issues went away. I can use images, move files, and even boot System 7.5.5 without any crashes or other problems. The BlueSCSI is most likely bad. I'll probably have a follow up thread in the future when I'm motivated to work on that, but for now I'm happy that I have a solution that works (and that the SE itself seems fine)!
