A check in from the student of military history (sorry, I had to.)
300 Spartans
700 associated other Greeks
Herodotus puts the number of Persians at over 5 million. It might have been possible, given the size of the Persian empire, but it's unlikely. I believe Thucydides dismisses the estimate. However, modern historians consider over a million to be perfectly reasonable.
The phalanx was broken because a hoplite phalanx, by definition, only faces one direction. You're thinking about a Swiss or Scottish square when you say you don't know why they broke when attacked from behind. And as regarding CC Spartans... sorry, pal, you're out of luck. A single Spartan was dangerous, but the great strength of the Spartans was in their teamwork, which means that they increase in fighting power exponential to their number. One guy just isn't going to cut it.
