I realize there are some sources of ambiguity in this question: (1) what qualifies as "de facto leader" e.g. if the parliamentary system ends or becomes powerless to military control, and (2) if said de facto leader is a member of multiple of the listed groups.

In such scenario the question will resolve based on which "group" has more effective power i.e. if the country is under military rule but the army general happens to also be a member of the BNP it will resolve to military rule, but if the country is under normal parliamentary governance but the prime minister also happens to be a retired army general or something it will resolve to their respective party.

There is still some ambiguity if the situation ends up something like Pakistan; in this case I will probably resolve to a probability equal to the results of a poll.