EC2 - Shared Storage - S3FS or EBS?
Solution 1:
An EBS volume that pushes to S3/CloudFront seems like the best move here, especially if you're worried about images, CSS, javascript, that type of stuff.
EBS will be easier to snapshot/backup than S3, especially for the server's filesystem.
You could also designate one server as the "master" and another as the "slave" and only make changes on the "master" for instance.
As for logging, have a look at some of the cloud logging services like http://loggly.com/ or https://papertrailapp.com/.
HTH