DC/OS doesn't run Schema-registry and Rest-Proxy components of confluent 2.0. I've launched Confluent 2 that contains the apache-kafka package in DC/OS 1.7 via Marathon, see also the Marathon app spec. As I understand, Marathon runs kafka-scheduler.jar from kafka-scheduler.zip (cf. the Marathon app spec) via a script. I didn't find any option that can specify which component to run or alternatively the source of kafka-scheduler.jar.
The initial implementation of Confluent Support in DC/OS included only the Kafka Broker level. The Confluent and Mesos teams are collaborating on a more integrated offering that will include all the Confluent Platform components ... stay tuned !