Yes, you can install Adam alongside existing Hadoop distributions such as Cloudera CDH or Hortonworks HDP. You can use Adam to manage Python and R conda packages and environments across a cluster.
Currently, Adam offers full support for Amazon Elastic Compute Cloud (EC2).
Yes, you can manually create instances on another cloud provider and then provision the nodes. For more information, see Tasks.
For communication between the cluster nodes, ports 22, 4505 and 4506 are used to provision the cluster via SSH and Salt.