Why? (Referring to post before last, red writing has come up when I went to send this post)
One thing we NEVER know when researching family history is WHY! ! !
I had a family who had two children called William. Their first son, William Henry appeared to always be known as Harry, I assumed ( but will never actually know) it was to distinguish from Dad, also William. Then many years and many children later, they called their yoingest William. I liked to think (and again I will never know) that as the first one was very much a Harry, they were determined to carry on the family name PROPERLY!
We can only guess the reasons why people in the past chose a particular name, it is fun to dream up stories as to the possible reasons, as long as we keep those stories separate in our minds from the facts we are trying to seek out in our research. If the facts show they had two Marys, then so be it.