Jane and Alec's sister

After Aro saved the twins from the stake, he also turned their little sister Johanna. He watched as the villagers punched her unconscious before throwing her towards the bush he was hiding in. It has hurt his unbeating heart tremendously to hear her pained shouts in fear of her siblings life's while they stayed quiet as they have gotten bound up there. Only after they punched the tiny girl the twins shouted out threats. They were furious that they have dared hurt their beloved sister. And as they set the stake on fire, he quickly gave the sign to his two brothers to quickly get them down from there while he takes their sister into his arms. Careful to not hurt the tiny girl.
Ever since that day those three siblings have joined the Volturis and while the twins are highly appreciated there, everyone is head over heels for Johanna.
How couldn't they all adore the tiny vampire that cares for everyone she meets.

So how will the whole coven react when some of the Cullens come to ask for their help and turn out to be their sunshine's mates?
Most importantly, how will her siblings and their adoptive father react?