Were the 'Mothers of the Believers' Believers?

I have previously published a post entitled Was the Founder of Islam a Believer? Here I pose the question: Were the 'Mothers of the Believers' Believers?

S 66:5 Perhaps his lord if he divorced you would exchange for him husbands better than you, surrendering, believing, obedient, repentant, worshipping, fasting, matrons and virgins.

'[B]elieving' translates mu'minat. Likewise, we may also pose the question: Were they Muslimahs, 'those who surrender'?

Further reading:

Muslims and Believers

Were the Islamic Prophets Disbelievers?