They are all "available", but some may not have a mobile optimized skin yet. If you need the functionality of one of those components, either take the hit on performance, or create your own light weight skin in Actionscript.
The components that are not mobile optimized will be indicated in the API reference. I'm not sure if there is a list, but you can always click through the classes in the spark.components package in the API reference to see which ones are not optimized yet.
I couldn't see some in the components list in design view or get them to come up when doing crtl + space in FB.
on another note, how does AS3 get converted to objective c ?