hi bigbadwolf, do you happen to have a usb cable and port that you could try instead as a test?
it might not fix things but could help to pinpoint things a bit…
you might need to power all off for about 10 minutes before trying, though if it still does not work with usb, can i check which version of dashboard you are using?
(there was a new version released last month as version 3 and then the other day there was another version released as well and maybe those could be worth trying to install - and rebooting again to test?)
if dashboard can see it (and just not mounting on the macs) have you also tried disk tools that come with the mac?
(if you also happen to have access to disk warrior, that has been known to fix a lot of issues on macs in general, including das drobos like the 5D).