While you can deploy any instance type that meets the minimum requirements for CPU/RAM, we do have some recommendations. Use RHEL 7.4+ or CentOS 7.4+ on the newest generation instance types that come with fast local storage (i3, m4 and x1). The c4, r4, and m4 instance types are also a great choice, but you will need to configure some additional EBS storage. You will need 50 GB for the root/OS and 2 times the RAM (in GB) that your instances comes with. For example, an instance with 32 GB or RAM will need 50GB + 2 * 32GB = 114 GB of EBS (io1 or gp2) storage.
You can stop and start an instance that is using EBS storage. See the AWS documentation for more details http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/InstanceStorage.html#instance-store-lifetime .
For cluster shared storage we recommend using AWS EFS (https://aws.amazon.com/efs/) , an existing NFS share or letting our installer take care of setting one up for you. It should not be hosted on S3 as we require file system access semantics. If you're unsure or aren't familiar with shared storage, then go with EFS and let AWS manage it