Who do you think is Long's daughter?

[Silverobama]

Long is my friend and is also Kris' friend. Today I showed a picture of my niece and Long's daughter then I asked Kris "Who do you think is Long's daughter?"

Kris is my friend, too.

Is the italic sentence natural?

[jutfrank]

Is there a special reason why you want to refer to her as Long's daughter rather than use her name?

Which one do you think is [insert name]?

[emsr2d2]

If you're asking the person to identify which of the people in the photo is Long's daughter, then use "Which one of them do you think is Long's daughter?" Presumably, you're asking the person if they can see a family resemblance.