Your Targa and PCX work great on AROS One 68k, your Descriptors are like the ones I had created. "Targa" unfortunately does not have an undefined "Signatures Table" for recognition without extension, I had found a way to have the TGA image recognized without extension, but then I had to remove it and leave the standard Descriptors like yours, this is because many files without extension were seen as TGA images.
Your Multiview works fine and allows ILBM and PNG saves, the only problem I already pointed out to you is that the Multiview window cannot be resized.
Now on AROS 68k to complete, just missing the TIF.datatypes and the Midi.datatypes