Hi Sen,
1. The stack implements version 1.1.1 of the Thread Group core specification. The Thread stack has been certified by Thread Group. The are no plans to implement other Thread versions into the KW41Z platform, only maintenance.
2. Not within the KW41Z stack, that'd need to be taken cared of in the host processor. ie. k64+cr20a or external linux host
3. Just in the external host