The actual hex byte sequence that must be written to the file is 0x1b 0x25 0x47 (3 bytes).

ExifTool converts "ESC " to 0x1b only if there is a space after "ESC". Then it packs the remaining bytes by removing spaces and commas. Note that '%' = 0x25 and 'G' = 0x47.

So with your examples, either 1 or 2 will work, but 3 will not because of the way that ExifTool translates the escape character.