Somehow, it's timing out and also defaulting to the A4 paper size glitch.
There are entries in the ppd that control the default paper selection and printable area. They may be set to A4. You can get those defaults more reasonable. For example, there's probably a line in the PPD that's similar to
*DefaultPageSize iso-a4
and a group of lines that say
*PageSize xxx/yyy:
...
*End
Simply change that DefaultPageSize to one of the "xxx" entries (before the slash) that represents the default page size you want.
The same goes for DefaultPageRegion, DefaultImageableArea, and DefaultPaperDimension settings if they exist.
Now, if you get any brainstorms how to add all the Canon utility functions such a nozzle checks, head cleaning, ink levels to the PPD file.... I would be very grateful.
I'm afraid if you want those function to work, you'll have to stop using the ThinPrint functionality (disabling Printers in the VM's Settings), logically connect the USB printer to the VM when you wish to use it, and use the Canon drivers and other software in the VM. PPD settings don't control those utility functions.
Note that USB devices can only be in use by one OS at a time (either the guest or the Mac).