I agree with pretty much all, except the Hewitt bit.
The only thing Hewitt and Harry have in common is red hair, which also runs in the Winds and the Spencers. Harry looks a lot like many ancestors in the Windsor and Spencer lines.
Yeah I said don't just go by looks, but the timeline doesn't fit at all.
Crucially, Diana didn't even know Hewitt when Harry was conceived and born, he was employed as the kids' riding instructor when Harry was 3 or so.
Harry also looks a crazy lot like Charles, even their mannerisms and poses in front of cameras are the same. They did a tour together years ago and the resemblance was striking.
I find George to look a crazy lot like Mike, Louis is exactly the same as James and Kate with a bit of Mike on top.
Edward looks these days so much like Liz, you'd think he has no father and Liz produced him on her own. Louise looks a lot like Mary/Liz/Anne/Zara/Ed.