Just to be clear, you need the ATPL theory exams to satisfy an ICAO requirement that you need ATPL theory irrespective of which license you hold to get a type rating on a multi-crew aircraft. In days of yore CPL holding co-pilots without ATPL theory such as on the BA B747 Classic fleet found themselves trapped on type by this rule and, as I recall, many needed to pass ATPL theory in late middle age to upgrade to the B747-400 as it replaced the Classics, even though they knew they were never going to get command.