Members have no choice but to accept every jot and tittle of official teachings AND findings...
That's not really true- it's perfectly OK to not believe a particular apparition or vision, and I know Catholics that take their faith seriously, but otherwise are not particularly devoted to apparitions or the piety assosciated with that.
When the RCC approves of something like the Divine Mercy devotion, they aren't necessarily saying that a person has to believe Jesus appeared to a polish nun and taught her some prayers- they are saying the practice of the Divine Mercy is consistent with their received tradition and the Bible. The same is true with other devotions like the rosary- it's not necessary to believe any of the particular stories about it, merely that it is beneficial and consistent with the Catholic faith.
There are Protestants, particularly among some Anglicans and Lutherans, who do accept the reality of much of Roman Catholic religious experience, while still regognizing that the debates of Petrine supremacy and so forth that seperate Catholics from Protestants are not resolved. For instance, I am currently reading a book, written by a Lutheran pastor and writer, on Padre Pio of Pietrelcina, a mid-twentieth century Italian charismatic saint. And the former Anglican Archbishop of Canterburry, Rowan Williams, visited Lourdes and gave a sermon there. So there are Protestants that are not automatically inimical or hostile to Roman Catholicism and can recognize what is true and good there, there is no need to be a Christian and have an "us" vs. "them" mentality.
I might suggest that prayers to Mary are not optional in the RCC.
Mostly it is optional, yes. The only place it might appear is if the Confitetor, a confession of sin, is used in the Mass's penitential rite, and even then, Mary is not addressed directly, the Confitetor is addressed to the assembled faithful. "Prayers to Mary" fits more with private devotion, something people can take or leave as it suits them.
Lutherans and Anglicans, two protestant groups, absolutely do accept the idea that Mary prays for the Church, by the way. The issue for Lutherans is the propriety of asking saints to pray for us- some Anglicans even accept this practice, others do not.