I assume the probability of all these "theories" is the same as the case of 3 (three) ADIRUs failing, close to 10exp-9 (for those of you better versed in the terminology). For others - 10exp-9 is close to 0. In general, reliability and maintainability analysis usually treats this as a non-existent case, only theoretically possible.
In addition, for all the speculations regarding structural capability of A330-200, documentation on certification of that article is widely available. Simply said this airplane was tested (and proven airworthy) as per relevant transport aircraft category requirements (Part 25). Everything outside of the tested envelope is purely theoretical and can be covered with additional documentation from delegated authority (EASA in this case).
Everything else is unfounded speculation.
Just 2p from the structural/certification side.
Cheers