Best Answer: Several of those persons in your list seem to be persons who are living, which translates into, unless they choose otherwise, their ancestry can be considered private/ confidential information.
The ONE reliable way to verify their ethnic background is to trace their lineage, AND find substantiated records that prove where the ancestors originated. It is extremely probable that this is exactly WHY YOU are getting conflicting info. The person posting it, is not the one who has valid records, and is not always bothering to insure that they have accurate records. They may have good info.. they may be little more than spreading rumors.
It can go either way, when dealing with a celebrity. You MIGHT find reliable ancestry facts... or the person involved may make the legitimate choice of keeping their family information private. It is a toss up.
Naomi Campbell - African, Chinese (parents where Jamaicans)
Trent Reznor - I think his surname is German
Justin Chambers - Irish, German
Patrick Dempsey - Irish
Yvonne DiCarlo - Scottish, Italian
Agnes Moorehead - English, Irish, Scottish, Welsh
Ava Gardner - Irish, Amerindian, Scottish English
Dog the Bounty Hunter - His surname (Chapman) is English
First, they might have changed their names when they became actors so those names might not be their birth names. Not to mention, the female names might be their married name.
Their ethnicity depends on their parents and grandparents so each one would have to be researched separately.
You probably would want to search for their tree as an individual, not as a star. www.genforum.com and www.gencircles are two good sites that might have information on each of them by family researchers, not those just looking to put up a tree, right or wrong.