The drive's format will certainly mount in OS X. That's not an issue. The (few) SCSI -> USB converters that were around back in the day are probably iffy with notebook-sized drives, and the cable adapters are probably beyond rare for those that WILL work.
Your best bet would be to set up a network between the two with one of those good ol' AsanteTalk localtalk to 10bt adapters. Or you can do AAUI to 10bt. AppleTalk, though, may be a bit sketchy since I'm not sure if AFP over AppleTalk works at all with newer versions of OS X, and I don't think AFP over TCP/IP is supported on 7.5.5, even with Open Transport. I don't remember all that crap anymore.
I vote running an FTP server and using Fetch. Or doing a null modem xfer with zterm.
(Is the old unit dead? That would make things easier to figure out)