Any issues on this to do with photographing people are not covered by copyright law.
According to my knowlege it makes no difference if the person is being photographed or illustrated - in any case you have the to ask a person for permission for certain types of publishing(not just celebrities)
As I say, "there may be other issues in some countries such as model rights", but this isn't copyright law. The point I was making is that the laws on model rights, or how one random application store decides to enforce them, doesn't tell us specifically about how things might work for copyright law.
Also when you say "the person" being illustrated. In your example, we're not talking about an illustration of a real person, but also that you are copying a fictional character, which is where the copyright problems come in.
