Questions about calculations involving bones

Just starting with Daz scripting, so expect a whole sequence of newbie questions from me.

I'm trying to do some calculations involving bone positions.  I've read the documentation on DzBone and its base classes, and I do understand the difference between "local space" and "world space" when it comes to positions, rotations, etc.

Questions (all in the context of DzBone, even though many of the methods are in DzNode):

1. I assume that the "location" of a bone refers to its root (for lack of a better term).  Given the location and rotation or transform for the bone, how does one calculate the position of the bone's tip?  I see the DzNode.getEndpoint() method, but uncertain what space that is in and how it relates to getLocalPos()./ getWSPos()
2. How does the return value of DzNode.getOrientation() differ from the return value of DzNode getLocalRot()?  
3. For items that take a Boolean defaultVal=false  argument, if one passes in "true" for that, does this give you the value as if the bone's "positioning controls" were all set to zero?  (i.e. as if the bone in the figure is in the default pose's position)?

Thanks in advance!