The 3rd party application "MARS Emergency Alerts" for Cisco CUCM would be able to meet your requirements
1) Send Pre-recorded audio alerts - Auto Broadcast audio alert/Message
2) Send Text alerts
3) Send live audio alerts- Auto Broadcast audio alert/Message
4) Dial a number/s and when the called party answers the call - play out a pre-recorded audio alert/Message to the called person/s
For further details please write to firstname.lastname@example.org
In Advanced (AdHoc/Live/Pre-recorded), in our experience as SInglewire, there are many ways to manage the CODE BLUE workflow, we can certainly run through a best practice meeting. Basic paging is only live audio, IP phone to IP Phone. In Advanced you have a standard feature called DialCast the, when the number is entered from a licensed IP phone, will trigger an immediate alert on the pre-defined workflow, we call it message template. Feel free to ping me if you need more on email@example.com.