I think you did really well @swamidass. And I have to say I think Behe was extremely confused on the topic of exaptation. Clearly the taking of an existing structure and rearranging it so it serves another function is an example of exaptation. Under that clearly canonical definition of exaptation, Michael Behe is demonstrably incorrect to say there have been no examples of exaptation resulting in novel functions and structures in experimental biology.
Just to pick one recent example I wrote about on this very forum, the rearrangement of parts from different genes resulted in a novel chimeric transporter:
Here’s an example where gene fusion of different genes (the exaptation of parts already existing of protein coding genes serving other functions) results in a novel function:
Of course, the repurposing of the promoter for the rnk gene which occurred spontaneously in the Lenski long-term evolution experiment, through gene duplication, resulted in a novel phenotypic function: The Cit+ phenotype. Hence it is another textbook example of exaptation resulting in a novel function(see figure for how this occurred):
I have a post on Panda’s Thumb explaining how experiments have shown that pieces of already existing protein coding genes can be copied and rearranged into new functional genes, which would also qualify as examples as exaptation: