AWS organization: What is possible as an admin?

I have a question regarding the possibilities as admin of an organization. The plan is to link an external AWS account of a freelancer to our organization.

After some research it turns out that the instances remain invisible to colleagues from the same organization. AWS sees these as 2 personal accounts with personal instances. But we want to keep an eye on our freelancer. AWS organizations mainly serve to work from the same bank account. But that's all.

Is there a way to see how many instances your organization has? Or to see how much that specific account spends from the common account?

Do you see other ways to keep an eye on the freelancer?

Thank you in advance!