Toad - A brick rig would count, yes. If I see it, it counts. But, if you happened to mask it out completely, then I couldn't see it.
1 - Nope. That's fine.
2- "Per the original contest rules, even effects like flying sparks would count as an "element/brick." (So, a puff of CGI steam would count as 1 "brick.")" So yes, draw one eyebrow, that's one "brick." Draw two, and that's two "bricks."
3- I'd rather you didn't. The rules only explicitly call out minifigures, and I'd include minidolls with that, but as for "bigfigs" and Dulpo figures, the rules didn't specify this year. You're free to use them, but remember, this is a great time to stretch your creativity. I'd recommend avoiding them, but if you want, they are allowed.
Don't forget the spirit of the contest guys. Yes, there are some loopholes, and yes, there is some wiggle room in places, but don't forget the core intent of severe limits to test creativity and ingenuity. I don't mind questions at all though. I'm glad to make things clear.