they want to be used. It is annoying but that is the way it happens.
I have books about names. They make fascinating reading. I once picked up a second hand copy of a book called "Names through the Ages" by Teresa Norman. It starts with "the Dark Ages" in England and names like "Acha" and "Aelfgifu" for women and "Adelhard" and "Adhelm" for men. It covers Scotland, Wales, Ireland, France and the United States and is one of those "useful books" that has a place on a (would be) writer's reference shelf.
But someone has just asked me why I called two characters in what they are reading by such similar names. There are actually three characters who share the name, one of them is their grandfather. He is not referred to by that name however but as the grandfather. The other grandfather, mentioned just in passing, also has that name. This is what happened. I tried other things but the characters kept telling me it was wrong. One boy has the English language version of the name, the other boy has the French version of the name. Their grandfathers would have been in the same position. The spelling is slightly different. The pronunciation is quite different. The boys are cousins. At the beginning of the book they have not met. They do not even know of one another's existence.
The adult reader asked if my choice was deliberate. The answer to that is, I think, no. It happened. It seems right. If it ends up being confusing to the reader then it will need rethinking but that is what the characters are telling me. It is also what happens in families. The same name or similar names get used between generations. My father and brother share one name which has been in the family for generations. My nephews are named after parents and grandparents. My niece has her great-grandmother's name.
I am named after a paternal aunt my father never met. She died young. We have a photograph of her. It was years before we saw it. When my cousin was writing up the family history for that generation he finally found a photograph of her. When he showed us my mother went quite pale. I look uncannily like my long deceased great aunt.
Names are not always easy. Most of the names I have used have turned out to be perfectly reasonable and sensible. Can you argue with John, Peter or Ruth? Is Lawrence or Miriam really that extraordinary?
I think Michael/Michel can work but, if it does not, then I am prepared to listen. Whether the characters will listen is another story.