Will I be reunited in Paradise with the husband from whom the legal contract was فسخ (annulled) under duress, and is the father considered unjust, and what is his recompense?

If a divorce is issued by the husband against his will, meaning he was genuinely coerced without just cause, then it is not valid. Not every threat to the husband is considered coercion. As for your father, if he sought your divorce for a valid reason, such as your husband's injustice or transgression, then he is not an oppressor. However, if his action was without a valid reason, then he is an oppressor who has committed a grave sin, because "a man's endeavor to separate a woman from her husband is among the most severe sins, and it is an act of sorcerers, and it is among the greatest deeds of devils."