Is it permissible to supplicate that Allah unite two people in Paradise if they did not marry in this world, and each of them married someone else?

A woman will be with her husband in Paradise, or with her last husband if she married more than one man and she and her husbands entered Paradise. However, it has not been reported that she would be given to someone other than her husband, and supplicating for that is an تجاوز (transgression) in supplication. It is better to ask Allah for ease in affairs and provision in this world, or for a better provision. For Allah knows and you do not know, and Allah may place much good in what is disliked.