How do I properly mount fat32 flash drive for Multisystem use?

Question

I'm attempting to switch to MultiSystem from YUMI so I can add ISOs to a multi-bootable flash drive with Ubuntu instead of Windows, and boy, am I starting to regret it.

• First, I backed up my flash drive to my internal drive.
• Using the Disks tool, I format the entire drive (MBR/DOS) and create a single labeled partition of type FAT32.
• I mount by selecting my drive in my file explorer, then try to use the Multisystem script but the list of drives is empty. Multisystem says it's looking in /media , but that's where it's mounted (/media/myname/drivelabel
• I try running Multisystem from the console as root, but it fails with error "Not root!". Oddly, when I run it normally (as my own user) I don't get that message. (I later suspect this is a mistranslated "don't run as root!", perhaps?)
• I give up on that method and try other avenues, such as burning the Multisystem-preinstalled ISO onto the drive instead, to no avail.
• I try mounting the drive before running the script, using my file manager.

I get an error in both Dolphin and Nautilus:

An error occurred while accessing 'CPDmulti', the system responded:
The requested operation has failed: Error mounting system-managed
device /dev/sdc1: Command-line `mount "/media/CPDmulti"' exited
with non-zero exit status 32: mount: unknown filesystem type 'fat32'

• That's weird. Shouldn't FAT32 be universally readable? I do some research and try umount -t vfat /dev/sdc1 /media/drivelabel which works. However, it still doesn't show in the list.
• I try to mount manually in a /media/ directory subfolder instead of the /media/username/ directory subfolder.
• This works! Apparently, Multisystem can't handle the normal /media/username convention and needs it mounted right in /media...
• Multisystem fails to continue. Error: Do you have write permission in this folder?: /media/CPDmulti...
• I check, and it's right - I can't write in the folder. I try all the chmod and chown tricks I know, but the mount command always makes it read-only. I can't mount as my own user, either, only root can mount.
• After research I learn that the graphical environments use udisks2 to do their mounting, which firsts mounts as root, then gives the created mount folder permissions to be accessed by the user. That's how it get around the above.
• So I try to invoke it myself: udisksctl mount -b /dev/sdc1 and whaddaya know.

I get this again:

Error mounting /dev/sdc1: 
GDBus.Error:org.freedesktop.UDisks2.Error.Failed:
Error mounting system-managed device /dev/sdc1: 
Command-line `mount "/media/CPDmulti"' exited 
with non-zero exit status 32: 
mount: unknown filesystem type 'fat32'

• Gah! How can I pass it the that vfat workaround? I try various versions of udisksctl mount -b /dev/sdc1 -t vfat which checks out with the help text. Doesn't change anything, though.

In summary, while I obviously need a way to get this script working, my more general problem is that I can't seem to naturally mount fat32 volumes. What if I need to read a FAT flash drive? This is Kubuntu 17.04. Have I found a bug, or is there something I'm missing?

Online I see solutions to mount: unknown filesystem type 'vfat' but nobody really has the mount: unknown filesystem type 'fat32' problem (wheras vfat works fine for me). Thanks in advance.