Flash app maxing the CPU - AS3 Optimization best practice?

I have experience in AS2, but am pretty green when it comes to OOP and AS3. Somewhat optimistically I’ve launched into AS3 by building this app: http://www.irideparks.com/demo_builder - as you can see it gets the CPU going!

Been racking my brains (and google) to figure out how to optimize/speed up this app - so a few questions:

Is it best/fastest to retrieve and loop through the display stack itself:

for (var i=0; i < container.numChildren; i++) {
var mc = container.getChildAt(i);
}

  • or create an array of references when adding the clips then looping through the array?

When there are a heap of clips on stage like this, is it be better to cache the parent clip (in this case the scrolled clip) as a bitmap? if so, how is best (link?)?

Is there an easy way to check for orphan events? i.e. a missing removeEvent.

These are the things that spring to (my AS3 limited!) mind that may be taxing the CPU, but any other advice would be appreciated too! Thanks in advance!