Send Change Data Capture events from Managed Package

Question

I am wrapping my head around the question of how to leverage Change Data Capture events in a customer's Managed Package app. They want to define a handful (= 10-15) of the packaged Custom Objects to send out CDC events, so external consumers can react to such changes.

Here are my specific questions:

1. Can I package a CDC definition or just triggers? 
2. If I cannot package them how can I define why CDC events my package emits?
3. In case I have to enable it via subscriber (Apex + MDApi) how can I ensure the subscriber cannot do it on his own?
4. The standard limit of CDC definitions per org is
5. How does the HDV Add On work?
6. Do I buy it as ISV or per subscriber? 
7. How much will it cost approximately?

Answer 1

1. You can package selection of objects for CDC.

2. N/A - they're packageable.

3. N/A.

4. The limit no longer applies to managed packages:

The maximum number of entity selections of 5 applies to selections that you make, or selections made by an unmanaged or managed package, except for AppExchange packages. If you install an AppExchange released managed package, the selections made by the AppExchange package don't count against your org's allocation.

This hasn't always been the case; early in the feature's lifespan, the lack of namespaced limits made using CDC in a managed package a non-starter.

However,

For package developers, the entity selection allocation is still enforced in the package development org.

which suggests you will need to purchase an add-on license for your packaging org if you want 10-15 definitions. I have not done this myself so I can't swear to the process.

5. I do not know the answer to this question.

6. The documentation suggests that you purchase a license for your packaging org as an ISV, but I do not have firsthand experience.

7. I cannot answer this question.