It certainly would have been different! One point of which would have been that Reinhardt would have been recalled from his posting to visit the wedding, and would have been set to take up the mantle with Ortrud marrying. So you would have gotten way less warning about Nordland, which would have been quite bad, but you also would likely get full state troop reinforcement from Ostermark rather than just some cobbled together mercenaries that Ortrud pulled up in DoDa canon. Also Middenland would be liable to start pushing north through the mountains and then cutting in, due to the difficulties of the plague barriers to the south. Westerland could have shoved in more people, mercenaries, etc. while Laurelorn would have deployed way more than just a few scattered squads, more on full extermination army deployment, if they felt pushed far enough.