The La Salette crucifix.

As I mentioned in a post from Friday [The apparition of Our Lady of La Salette] I've only just learned of that particular apparition of the Virgin Mary. I receive daily email from A Moment with Mary and this is where I first learned of the two children who claimed to have seen the Blessed Mother in 1846.
After a number of investigations, the Catholic Church found the claims to be credible.

Of course,like with all apparitions of the Virgin, there were those who doubted the claims of the two shepard children. At one point, there was a group who claimed that the lady the children saw and spoke to that day was not Mary but, "a lunatic nun named Constance Lamerliere" dressed in the strange costume.

This was also the first time I had seen a "La Salette crucifix" which the children say Mary was wearing around her neck. Seeing this crucifix leads me to ask a few questions.

Was there any use of this crucifix in the Catholic Church prior to the La Salette apparition? If this was a hitherto unknown crucifix, how could a "lunatic nun" have designed and crafted one? I'm not buying the "lunatic nun" claim.
If the children were lying about the apparition, where did the idea for the crucifix come from?

According to a wikipedia article,
"The La Salette crucifix, worn by the Virgin Mary, was unusual because it has added features, a hammer, a pincer and a skull and crossbones.
The hammer symbolizes the sinner nailing Jesus on the cross by his sins and the pincer represents all of us trying to remove the nails from the cross by our virtuous life and fidelity to Jesus. The skull and crossbones represent in general death, which is inevitably for human beings, as reminder of the necessity of personal salvation."

Are those who doubt the apparition saying, then, that the La Salette crucifix is the design of a fourteen year old girl and eleven year old boy?