Sorry for the delay here, I actually thought I had answered those questions on Friday but apparently I didn't? Weird...
- October 21st is indeed the deadline.
- Large does mean HeroScape Large, which does make it slightly tricky since that seems to be able to be called medium or large depending on where you're looking for minis.
- Exactly two special powers means just that, if one or both of these is a special attack that is a-okay.