Link to API DOCS
1.) After successful import of a bank connection you can call the service "Get all bank connections". The update status and the categorization status of all already imported bank connections can be checked here.
2.) The service "Get and search all accounts" delivers several information (e.g. account name, account number, account type, balance and much more) for each account.
Please note: The balance may be null if the import is still running or has failed (check if the status is UPDATED).