HI there Morgan,
What I've found out so far is that if a person is Living, but not a WikiTree member, then their information is Unlisted and super private. Trying to create a Fan Chart with their info gives the blanks you're talking about. Even WikiTree members who have Unlisted or super high Privacy settings for themselves, even when logged in, will also get those blanks.
HOWEVER ... (I did this for one of my sons as a test just last night because of a similar question to me) ... if you go to your family member's profile, and enter an email address for them - THEN - they will get an email invite to join WikiTree. They can then follow up with that - and it's a very easy process - click on email to confirm, and setup a password, then they are in! At that point, then they can go to the Fan Chart (My WikiTree -> Family Tree & Tools -> scroll down to Fan Chart), and produce the Fan Chart for themselves.
Not sure if there's another way to do this, but, that worked for my son. AND .. good news for me .. since I created his profile initially, I'm the profile manager, and once he became a member, I can create a Fan Chart with him as the starting person, and it shows up for me.
Hope that helps.