We never heard of mini-missionaries when in America; however, that is not to say that there were not mini-missionaries there. We just never heard of them.
In Hungary, and I assume in other countries, youth of the Church sometimes serve as mini-missionaries. From our youth group, we have had three such mini-missionaries since we have been here.
One was Norbi, Timi’s brother. He served three weeks while the mission was waiting for another missionary to come to replace one who left early. He is 20 and since this service, is contemplating serving a full time mission.
Another was Barbi, who has served three other mini-missions. Her picture was in other posting. She is also 20 and would like to serve a full-time mission for the Church. The third is Adri, the President of our YSA Council. She is serving for six weeks, until another sister missionary comes in December. (One of her sisters is serving as YSA President until she returns.)
These missionaries live with their companions and live the same lifestyle as their companions. They arise early, have their morning prayers, study the gospel, study the language and follow exactly the same rules as the full time missionaries. They are very valuable to our Mission. Instead of having to have a three-some set of missionaries for several weeks and shutting down an area where they had missionaries, they are partners to a partner-less missionary who has a specific area to work in.
Sister S and Sister C are being successful; I see that they have three baptisms scheduled soon. In my opinion, having native young Hungarians preach the gospel is great. The missionaries from other countries are effective; but in a country where the Church is relatively unknown, Hungarians might be a tad more interested in someone from their own country preaching to them. (Same in other countries!)
Today, one of Barbie’s converts from her mini-mission in Miskolc, came to the Mission Home to visit and attend Institute and Barbie, who was there for Institute, was so excited! It was a wonderful moment for these two sisters in the Gospel to see each other again! You can see how valuable these mini-missionaries are!