I imagine the response to this may be "That's ridiculous! Why is the earth flat, but the other planets around it are not? How is it so different that comparison is insufficient? It makes more sense that the Earth is round like the round planets around it."
And the response to that is "well the earth is special. It is large, it has its own sun to warm it and it is the only place we find life. It isn't like the tiny twinkling planets you see when you look up. "
If the sun is no more than 32 miles across ... how big is a star placed not much different in altitude? The size of a double decker bus? Maybe we need to make much more out of how very different earth is from planets. People have been taught earth and planets are the same, stars are different. We need to be saying stars and planets are the same, earth is different ... which is obvious to anyone with a pair of eyeballs.
It depends on what you want an FAQ to be. Usually they are used to blunt an onslaught of common questions from being asked over and over again in a short, terse manner. You can always link off to a more in depth examination. But an FAQ should weed out a bunch.
I think what people get from school and media is that we learn there are 3 things out there: Planets, of which earth is one, moons that are 'attached' to planets, and stars, of which the sun is one. That's kinda the core belief system. Then with FET you kind of get four, the 4th being earth. I don't think it's a leap from there to make a case that earth is fundamentally different from the other 3, hence the insufficient comparison. Easy explanation, to your point Thork, it's the only place we find life. Doesn't get more fundamentally different than that.
So my point is that if the fundamental difference(s) are not already known to the reader, there's not much more you can say to convince them otherwise.