It is not MY definition of legitimate, but Merriam Webster
's definition and implies the concepts of "rule" and "standard".
The rules and the standards, different concepts, are determinated by the group of people who have the authority, in some European languages one academy, in other European languages a mass of educated speakers.
On the other hand "standard" and "legitimate" are not the same. One thing can be "legitimate" and not be "standard" (as in the case of old variants, dialectal variants... that doesn't break the rules but are not the common ones).
In the example, if the subgroup using Qameron achieve that this spelling is not seen as odd / my-parents-are-illiterate-who-don't-know-how-to-spell / put any negative connotation and lecture associated to the spelling (that is why used "succeed") and Qameron become a substantially uniform and well established by usage in writing of the educated and widely recognized as acceptable spelling (that is, "standard spelling"), the English spelling rule would vary (from "Q can't precede A without a U" to "Q can represent the sound [k] directly before A") and the name [Qameron] would become legitimate (the spelling will be conformed to the rule, that will affect other words and names).
The use of "legitimate" in relation to names is relevant to English speakers. Googling "legitimate names" gives 17,800 results, "legitimate name" 59,500 results, "legit names" 930 and "legit name" 25,300; many of them, from the US, where any name can be legal.