Can SAP CRM be replaced with C4C for Order Management scenario in Billing?

Hi all,

I have some questions regarding an integration between Hybris Billing and Cloud for Customer.

[Background Information]

I am preparing for a solution architecture for a customer pest control and hygiene industry. Since they provide rental services, subscription order management is needed.

Solution proposed as tentative:

1. Commerce
2. Billing
3. Cloud for Customer Sales and Service

[Questions]

1. Can Cloud for Customer be replaced with SAP CRM in the slide below?
2. Is there any customer references that integrate Hybris Billing to Cloud for Customer for subscription order scenario?
3. If yes for the question 2, what level of development is required?

I have attached integration Commerce B2C into Hybris Billing below.