RE: Human Pilot Figure
First off the rules don't state that the pilot must be an aerobatic lifelike pilot.
It does say a realistic 3D human pilot. I've attached the rule below. So no, Snoopy would not count.
A motorcycle helmet or F-1 driver is a 3D realistic Human pilot. Whether or not anyone choses to wear a full helmet in an airplane is up to them. The rule doesn't say that the pilot has to be an example of an actual pilot. If that was the case, then the one with the lady with all the cleavage wouldn't be "realistc" as she would fall out of that outfit.
As for saying that you couldn't wear a helmet like that due to G forces........Have you ever pulled 9G's before? Have you ever weighed the AF helmet with mask compared to a F-1 helmet? They are about the same. I've pulled 9+ G's in an F-16 numerous times and my head didn't rip off.....if anything your head is forced down into your body. If I did say -9G's then maybe your thought would have some validity.....but at -9Gs the last thing I'm worried about is my head ripping off.