"These women would be happy if you were to call them."
Translation:Queste donne sarebbero felici se tu le chiamassi.
I believe felice is one of those adjectives that has no masculine/feminine form. So its singular is felice and the plural is felici regardless of gender.
Remember that piacere has an "inverted" subject compared to like: the same applies to "fare piacere". A more literal translation would be "queste donne sarebbero felici se tu le chiamassi".