Toast 5 is first rate at making .toast disk images of Mac / PC and hybrid discs.
But Audio partitions are not usually picked up.
Options open to you come down to a choice of 2:

• Use Toast to save the Audio partition on a SoundDesigner 2 format, or .sd2f. This has been done here for many games, Age of Empires, Sam & Max Hit The Road, etc. Benefits of this is that anyone with Toast 5 or later can then burn the disc with Mac and Audio partitions, and that the user only needs to download and burn the Mac/PC part if they wish to for-go the Audio partition. Drawbacks are that it's slightly inconvenient and that because the Audio part is stored as a list of tracks, when it's burned, it may not be an exact bit-replica of the original disc.
• Use a different tool, like SimplyBurns for Mac or a long list of PC tools, to create a single BIN/CUE pair covering the whole disc. Benefits - it's a single pair of files for an exact bit-replica of the original disc. Drawbacks - you need a modern Mac and be willing to install the marginal software on it to burn the discs. Just not the sites target audience.

Cube crashing is a real nightmare. Does it run off an ADC monitor ? Just wonder if the PMU is having a turn trying to also control power to the monitor. Used to have the same with an MDD, on wakeup he screen would stay black. A new battery and a reset to the PMU would fix things for a few weeks. Changing from a 23" ACD to a 17" ACD helped immensely too. Finally, removing the display altogether and running it headless (via ARD) solved it completely -it could o to sleep and I could wake it with a tap to the power button.

Happens to me too, when you mount a Toast image of a hybrid disc (Mac & PC) it mounts both Mac and PC partitions. You can check this, perform a "Get Info" on the mounted discs in turn, one is "Mac OS Standard" (or HFS), the garbled one will be "ISO". Normally when you insert the physical CD, only the Mac part will mount and show in the Finder.

Cube:
Is it an ADC or BGA display ?
How old is the PRAM battery ?

Mounting PC partitions on the classic Mac OS is easier if you have Joliet Volume Access, available on this site, though for hybrid discs you'll seldom or never need to use that PC partition, so once you confirm it's there you can drag it to the trash to unmount it and just use the Mac partition still mounted.

The garbled files are the PC partition. They're harmless.

VGA monitor on the Cube is good, if it was ADC you'd have the Cube PMU also controling power to the display. Sometimes it's that that gets confused.

The PRAM holds the boot disk, clock, volume and the PMU settings. The PMU is the Power Management Unit, which controls power to all the attached peripherals (including the display) when the computer goes to sleep and wakes up.
Issues with sleep may be most likely issues with the state of the PMU. If it turns out the PMU is fine, we'll look at the OS.

A simple check is if you shut down and unplug it. Leave it for 10 minutes, then remove the Ethernet cable and start it up again. If it has kept the correct time, it's probably fine. If it's reset to 1904 or 1970, the battery is dead.
You need to remove the Ethernet cable so that it doesn't pick up the time from a Network Time Server.