That's good, because Steve (Kunkel) originally volunteered but is going to be unavailable for some months for personal reasons...
I contacted Tom, the Czech author of AltSearch, about our needs.
He has modified AltSearch to extract bookmark links from a document. (AFAIK, he has not implemented extraction of headings so far.)
He sent a beta to me for testing, with instructions. But there may be some communication gaps, because I am not getting the results we expected.
We are supposed to give proper feedback to Tom so that he can make further changes to AltSearch, to make this work.
Can I share the mails from Tom with you? (If so, please send your email ID through a pm). Thanks!