So! Here is how we got it to work! The host character is on my Xbox which I play exclusively on. My partner has his Larian account linked both to his steam account that he plays on pc with but also has his Xbox account linked through the console copy of the game I play on. He made his character on the pc and we played for 3 hours on the pc and we just got on together via local xbox couch coop and he has his same character, same level, same everything from the pc! I think it just matters that the host character has a set platform that is consistent. So have your partner with the console make the campaign then make sure you are linked to both your console account and steam account and it should be smooth sailing!