Scripture is clear about women in leadership positions in the church. So I don't think women should be pastors in authority. I do know of women who have been credentialed as pastors for the sole purpose of visitation in hospitals for women patients. Sometimes that's a lot less awkward than having a man do it.
And I don't think that precludes women from speaking in the pulpit. If a church has a missionary couple in sharing what they are doing, I see no reason that the woman can't expound on that.
However, preaching the gospel to others is NOT prohibited by any means, neither is prophecy.
Proverbs 31 describes a woman or noble character, one who certainly can hold her own and make wise decisions of her own.
The first Evangelists proclaiming the good news of Jesus resurrection were women. When they left the empty tomb...”He is Risen”.
We are probably stumbling over different definitions. We wouldn't define a person in hospital ministry as being a pastor; neither could a non-ordained person administer most of the sacraments (except a lay person, properly commissioned, could bring the Holy Eucharist to a sick person.) But that does not require a pastor.
As for the "missionary couple sharing their experience," that would not be "preaching" as we understand it, i.e. expounding the Gospel from the pulpit during Mass. That is to say, Liturgical proclamation, which is done only by an ordained man: deacon, priest,or bishop.
The "missionary couple" might rather talk to a special meeting in the school gym, or to the Youth group or the Council of Catholic Women or something.
Outside of Liturgy, as to general "preaching," --- sometimes you can't shut me up! Ask my husband! My very patient husband!! :o)