I guess we all go through various phases and occasionally use a different name for some of the phases. Nothing illegal with that. Nicknames sometimes have a way of sticking better than our given names. Some first names are hard to pronounce so they are changed to make them more understandable. We have all seen that.
Francisco becomes Frank, Cristoval becomes Chris, Paulino becomes Paul. The list can go on and on. Sometimes, over time, the real first name is almost totally forgotten. I have a first cousin who is angry at my grandparents for giving their children such hard names. I really do not thnk they were hard at the time. They became hard as time wore on. I am sure that is why my mother used Ruby instead of Refugio.
I had an unusual experience in 1952 when I was enrolled at the first year "Saint Anthony's Catholic School" in Pecos, New Mexico. All the teachers were nuns from the Midwest. They had some local ladies to help them out as the kids mostly spoke Spanish. At our first recess we all had new names. Names that reflected our own real names but still different. Just as detailed above. It was funny and we did not know what to make of it.