Also means that Hanover is split from Britain near a century sooner. That would have some interesting effects on any German Unification.
I think German Unification is still a rather long ways away from even being an idea, much less a plan. AFAIK nationalism wasn't a big thing before the French Revolutionary/Napoléonic Wars.
Though I do find myself wondering about the marriage-game. Augusta was married off to her Welf cousin OTL as a way of the Hannoverian and Wolfenbüttel branches making nice. (George II apparently originally wanted George III to wed Sophie Antonia of Wolfenbüttel, but the boy refused, screaming "I won't be be-Wolfenbütteled", so a match between Augusta and Karl II happened instead). Here, England isn't going to like the idea of trading Hannover for some other German albatross, so Cumberland most likely gets a Wolfenbüttel match instead (if he isn't married yet), maybe Juliane Marie/Theresia Natalia of Brunswick for him?
As to Augusta, a second or younger son Protestant husband would do. Problem is, the "major" players don't have those (second sons or those that do aren't Protestant) while the "lesser" players that do, are perhaps not considered important enough for a future queen of England.