A company provides internet-based applications using an Amazon Route 53 public hosted zone as the authoritative DNS service for its domain. A network engineer is developing a new version of one of these applications, which is entirely hosted in AWS and follows a three-tier architecture. The front end consists of Amazon EC2 instances in public subnets with Elastic IPs, while the backend components reside in private subnets using RFC1918 addresses. The application components must communicate within the VPC using the same host names as those used over the public internet. Additionally, the solution must support future DNS changes, such as adding new host names or removing existing DNS entries.

Which three steps should be taken to fulfill these requirements?