Good morning!
Oh, I bet you can't wait! It's been such a long time (for you all!).
In our situation with Harry - we only have him, we got him at 12 weeks and he's 11 months old now. So after leaving his 'other mummy' that's all he's ever known. I'm at home a lot though, and he's usually with me/us when we're out.
I realise that we don't make up for other dogs - and that's what your little Rosie is used to. That's the difference, isn't it. I really think you're just going to have to wait and see, obviously there's going to be so much fuss and love and attention lavished upon her that she'll probably absolutely adore being the 'only one'. I do hope so.
Apart from that, we socialise Harry a lot in parks etc etc - and occasionally I take him to the pet-sitters for a day. He has fun while he's there, but is usually tired and grateful to be back home and having us all to himself!

Or, have you ever considered doing pet-sitting yourself?!?

Hope Friday goes smoothly and happily for you! Sally + Harry x