I don't think it'll need any drivers for SCSI support, I don't recall ever needing drivers for Newer's SCSI MicroDocks or the Apple MiniDocks which, IIRC, were OEM'd by Newer. Dunno if the EtherNet drivers are in ROM or not, but it wouldn't surprise me a bit if they were.

I'd say try to boot the Duo off a System Installer CD as well, shouldn't be a problem with your 600e.