Author here, funny to see this popping up on HN :) Was definitly a fun ride making this.
I've used your article and other previous attempts to clear up the remaining unknown bits of the file format and build apple-peeler, a tool for extracting the XML from the dictionary files.
Just to mention that Core Foundation includes tokenisers (CFStringTokenizer) and lemmatisers (NSLinguisticTagger) of its own in case you ever wanted to avoid the Python processing!