Is the suitor considered oppressive and hesitant, and is it permissible to say "Hasbunallah" against him and mention his flaws and stances to the family?

If the engagement was broken off due to the suitor's hesitation and actions indicating his regret, then there is no blame upon you. There is no harm in informing your family of the reason for the annulment to the extent needed, and do not speak about him beyond that. It has not become clear to us that he committed any injustice that would permit supplicating against him, and the saying "Hasbi Allah wa ni'mal Wakeel" (Allah is sufficient for me, and He is the best Disposer of affairs) is not a supplication against him. The suitor is a stranger to his fiancée.