HelpYouFindMe accounts are owned by each individual who created the during sign-up. Even in the event of sub-accounts. In other words, regardless of who is paying for the account, the account owner is always the person who registered the account. For information on account types, etc. see the terminology help page.
Regardless of account type, the management of the account is done by the account owner. This is the person who originally signed up for the account.
Not without specific permission. Data access in HelpYouFindMe works the same for everyone, regardless of family/sub account relationships.
This is not just our policy it's actually built into the application itself. It's impossible for us to provide the Family Account (or any other account or third party) access to a sub-accounts private data. This is because the data is encrypted on your local browser. We have no access to it.
Please get in touch with our support team and we'll be happy to answer them!