Get input from agent before placing an outbound call

I'm not sure I follow what you're asking. Do you need the agent to enter some DTMF or are you asking them to fill out some form? Assuming it's the form, you could create a form with then launches the CCP to place the outbound calll, but this isn't really a Connect issue, but more of something which should be done in your CRM or similar software.

The CCP is not customizable in anyway. You need to use the Streams API to do any customisation of an agent softphone.

With the Streams API you embed the CCP. You can then either hide the CCP to make a fully custom softphone or show it and use that for the normal softphone functions. If you show the CCP it is still not possible to alter anything within its frame.