Thanks @hhsu11 - I can investigate the issue with importing Disks myself.
(There is a pending update where stack traces will be offered as a text-file download rather than copy/paste - that will hopefully make those easier to provide, once we have a maintenance window to push that change)
It is possible, we need to create SheepShaver environments with a different Drive Configuration (under Details) to allow for mounting more floppies. Are you still using “Mac OS 8.5” and “Mac OS 9” to test the floppies? The double-mounting behavior is odd though - I will check with the devs.
Hybrid/mixed-mode CD-ROMs (with a data and audio track both present) can show up in Basilisk and SheepShaver as an “Audio CD” with one (non-functional) track. We’ve seen this before in EaaSI: Emulating Voyager disks, and as far as I’m aware it’s a limitation of ISO disk images vs the BIN/CUE format - which, unfortunately, default builds of SheepShaver (and EaaSI) do not support at this time. (As that other thread mentions, Geoffrey Brown created a fork of SheepShaver with BIN/CUE support for addressing Voyager Company discs, but, as I say, that build is not available to use in EaaSI at the moment)
Can you confirm that any ISO images mount properly for you in Basilisk and SheepShaver (for instance , this one from the EaaSI sample corpus? We could at least eliminate any more problems on the EaaSI side and try to focus on a work-around for the issue between ISOs and SheepShaver instead.