I'm going to do a joint birthday party for my 2 girls, read more below!?!
Go for a girlie pink theme. If you want to include their favourites how about party cakes with little toppers on top. Ebay sell lots of cake toppers in different themes. I recently bought hollywood ones for my daughters 21st. Perhaps have the party bags themed to the different styles as well.
As for games dont try to do too much, with face painting and disco you will probably find they have enough to do but speak to DJ they should be experienced at dealing with this and have some easy ideas.
Have a fun day and dont stress too much. x x
Perhaps you could have the party plates, serviettes, etc. in something suitable for both such as butterflies, stars, flowers or depicting party balloons...that way neither can be offended :)
To be honest I wouldn't worry too much about party games as you've already arranged fun stuff. The dj will probably be used to getting the kids involved. Perhaps you could check with him if he can do games such as musical statues or choosing the best dancer, etc.
I did pass the parcel at my son's party and there was lots of whinging from the kids that didn't win a prize (with hindsight should have put something inside each layer) ... wasn't like that when I was a kid...sigh...
hannah montana it will be awesome gift for both of them, what ever you planned all are right. Its obvious that you know choices for your girls better than all of us. Have a joy full birthday.
You could have a pink theme, half the hall with peppa pig things and half with hannah montana things.
maybe pass the parcel, musical statues.
A pink party is a really good idea