Any advice would be greatly appreciated.
Set up the separate account for the project with your son. Give him the password to that one, and then link it into your MCC with your other accounts. That way he will get to see just his one account, and you'll have overall access to everything.
Whether or not it makes a difference in Google's eyes that you are actually 'managing' the combined spend of the accounts - I have no idea.
Yes it does make a difference, at least at the agency level. It's not about managing the billing, it's about how much spend you are managing under your MCC.
I wouldn't worry about that, I would just set up an MCC to make your life easier in terms of day to day management of your accounts.
Yes it does make a difference, at least at the agency level. It's not about managing the billing, it's about how much spend you are managing under your MCC.
I know it makes a difference as far as qualifications for GAP, and it probably makes a difference as to whether you get a refrigerator or some other gift; other than that, what sigificance does it have to Google? I'm just curious.