DISTRIBUTION_ACCOUNT.STELLAR.DB_VAULT account type can hold up to 20, and Owners can add more at any time.
Access to an account is granted per user and is separate from the user’s role: both are required to act on an account. API keys need the read:distribution_wallets or write:distribution_wallets permission, and the Owner-only operations additionally require that the key was created by an Owner, so permissions alone are not sufficient. Accounts are archived rather than deleted, so past disbursements and payments keep pointing at the account that sent them.