There are hundreds of thousands of people who have returned to full communion to the Roman catholic Church as a result of Medjugorje. I am one of them. Before Medjugorje, I was pro-choice, indifferent to the Vatican and the Pope, probably more New Age than Christian despite having been "brought up" Catholic. As a result of my trip to Medjugorje in 1994, I have become strongly pro-life, truly believe that the Roman Catholic Church is the bride of Christ, I have great love for the Eucharist, and I am leading a Catholic Young Adult group that teaches according to the Catechism of the Catholic Church.
While I am aware of the bishop's statements, doubts and discouragements, the Vatican (higher authority) remains undecided, and has not prohibited people from visiting Medjugorje (but has prohibited priests/parishes from official organised trips there, to avoid the confusion about whether it is "approved")
Scripture states that we will know something is of God by its fruits. Jesus also states that "if they are not against us, they are with us.". The fruits of Medjugorje have far outweighed the negatives through the number of conversions & "reversions". Some of the most faithful, loving, committed Catholics in the church today had their "rebirth" through Medjugorje. If this place is of the devil, then God has conquered it and used if for the good. People going to Medjugorje fo to confession, go to daily Mass, and often participate in praying 20 decades of the Rosary daily. The priests in Medjugorje at a minimum "intend to do what the church does" which is the primary requirement for validity of sacraments.
Yes, there are things that are questionable, abuses of what may have happened there, and things requiring further investigation, but that has existed with every apparition site, and believing in an apparition is not a requirement of our faith. On the other hand, spreading the information below could potentially work agaisnt the Holy Spirit if the Holy Spirit is using this place to bring people back home. The Magisterium remains indifferent right now, so either promoting it (claiming is is gospel truth) or discrediting it (pushing that it is definitely false) is disobedient to the Magesterium....personal opinion excepted.
I could do an analysis of quotes by priests and bishops that are counter to the teachings of the church, and use that as evidence against the church. It doesn't make the Church false or invalid...but it is one of the main sources of apostasty today.
Please pray about what you are doing. I would strongly advise you to focus your efforts on living and teaching the gospel rather than disproving something that has been leading people back to the Gospel and the Church for 25 years. How disappointing that would be to go to heaven only to find our Blessed Mother sad that we deterred others from finding their way back to the Church and the Eucharist. The core messages of Medjugorje: Pray, fast, Convert, Go to Confession, Receive the Eucharist are all in line with our faith. We need to be getting this message regardless of where it comes from.
May God give you peace. In Jesus through Mary.