Admin edit S3 Media file?

1) Use persistent storage that can be shared among all EC2 instances within a region – Amazon Elastic File System

OR

2) Give developers access to the AWS console or AWS Command Line Interface to access S3 resources. In addition use AWS Identity and Access Management to limit access; whether it is read-only or read/write. With S3 access, web developers can download S3 objects, modify them, then upload them back into WP (via wp-admin) or S3.