Note however that the ZWJ prohibits breaking, despite in French there's a possible hyphenation at the first occurence, where it is also a syllable break, but not for the second occurence that occurs in the middle of the second syllable.
None of the rules in UAX#14 affect hyphenation.
A./
PS: since we have a perfectly fine AE as a character, there seems little gained in attempting a ligature. My suspicion would be that fonts would not provide the necessary mappings since the character code is available.
