NETCONF requests MUST be processed serially by the managed device. Additional requests MAY be sent before previous ones have been completed. The managed device MUST send responses only in the order the requests were received.
Yes, ConfD is fully compliant with RFC 6241, and note that the pipelining requirement in RFC 6241 refers to one NETCONF session. A NETCONF server should be able to process different sessions concurrently, as supported by ConfD.