Hasina will resign just after the unilateral election and will be arrested for killing 75 military officers in Pilkhana.
I don't think Hasina will ever be tried for Pilkhana. Even if she resigns, it will be on the condition of a safe exit.
What I'd like to see is the new government conducting proper investigation on that event and make them public. Even if Hasina remains in exile, just hit at her legacy.