I think the crown could be easily created (same result visually) without N-Gons, and obv. without non-planars as well.
What I did was subdivide the very top edge, then grab and snap to the lower edge. You get non-planars, but if you remove the faces and add extra geometry (at this point, it’s exactly the vertex-vertex-vertex fill that Mike did), you get the same thing. I really don’t see a point for the N-Gons in the crown after the spikes have been created.
Then I went a bit crazy and also removed the n-gon at the bottom. Triangles all around, everybody, get your triangles here!
