:::::FWIW, we deal with similar issues at WP:BLP/N on occasion, usually revolving around (alleged) real or birth names of people known by stage names (particularly pornographic actor/ess), although sometimes middle names or similar. I don't recall any other case involving a surname but I don't see any reason to treat this differently. We or at least I usually prefer to deal with it in a way similar to that suggested here. We definitely don't publish the info based on searches in primary sources like trademark documents, ancestery searches, tax filings, legal cases, etc. Instead we look for reliable secondary sources. One difference I perhaps have with the above, if the person is covered in more generalised sources I would prefer to find at least one instance of the usage there rather then solely going by specialised sources. (This somewhat reflects my experience, sometimes it may be the real name of porngraphic actor/ess was covered in reliable sources that cover the industry but I don't see the need spread the name when other more generalised sources have not.) However I can see this would go both ways, it may be generalised sources are not aware of the subject's preference in a case like this.