In the US there are no laws.
People can change their names to anything they want, and those laws vary from state to state - from simply taking the new name to petitioning a court, publicizing the notice, and if there is an objection the request is denied.
Different religions here have different traditions, which are about what is or isn't respectful or correct. I only know of the Judeo-Christian traditions: Christians name children after living people - relatives, close friends - as an honor or family tradition; Jewish people don't use the name of a living person.
As well, Christians, I believe, take the entire name when honoring the person or passing down a family name (Richard
, Jr), while Jewish people use only the first initial of a deceased relative and form a different name from it, of either gender: naming a child after a late grandparent, Richard
, would be any name that begins with 'R' *except* Richard
I was named after my greatgrandafather, Joseph
, who passed away before I was born. My middle name, too, has the first letter of my grandfather who passed away before I was born.