The captive who is owned is considered to be a fighting infidel, so it is not permissible to enslave the dhimmi, and it is the covenant between him and the Muslims.
And in the case of captivity, the woman becomes owned, whether she is married or not, and if her master wants to have intercourse with her, he waits for her to observe the ‘iddah of her husband’s water, then he can do that.
If the aggression of the infidels is against the Muslims, and the Muslims prevail, then it is permissible to take the women of the infidels, whether they are in the battlefield or not.