Would establishing Amazon's CloudFront having a custom origin being an ec2 server have performance increase to serving PHP with Apache? Essentially serving all of the dynamic content through CloudFront.

For reference my static submissions are already being offered through CloudFront on the seperate domain.

IF that's possible and offers a performance increase would you make a move like CloudFront which routes for an Elastic LoadBalancer which routes for an EC2 instance that has nginx like a front (have some static content this is not on cloudfront) which routes all php to Apache's mod_php.

You cannot serve dynamic content through cloudfront well whatsoever. Cloudfront does not accept Publish demands, also it strips querystrings from GET demands. Ref paperwork.