Have you implemented the 6LoWPAN adaptation layer (RFC 4944, 6282, and 7400) and 6LoWPAN-ND (Neighbor Discovery) (RFC 6775, 8505)?

No - not yet at least.

any partial implimentation of said protocols?
one more, what is the routing protocol implemented?
Is there are a way that I can see the documentation of stack, modules, or libraries, for example, Doxygen?

Are you talking about the FreeRTOS+TCP Labs project that supports IPv6? If so it is an upgrade of the extensively documented existing but IPv4 only stack. The labs project will eventually become the mainline version, but at the moment the only info is here: https://www.freertos.org/FreeRTOS-Plus/FreeRTOS_Plus_TCP/IPv6/index.html That page provide some info on the differences as far as what is available in the IPv6 version that is not available in the IPv4 version.

Well…, the RPL protocol is out of the question here if IPv6 is under development.
Thanks Richard for answering.