Are there any particular activites that they enjoy that you could arrange to do as a family to kind of draw them out?

First, they're at that age. Second, they have each other, you're just "Dad" right now. Third, they will come around. Lastly, establish boundaries, set the rules, let them know they are the most important people in your life, watch them closely, and set a good moral example, no matter how much it curtails your personal activities. It isn't now that counts, it's the years forward that do. When they look back and review their upbringing, they will know you sacrificed for them because you loved them so much. That's fatherhood, but I think you know that already.

If you had two boys, I'd recommend "A Father's Guide To Raising Conservative Gentlemen" on Amazon.com.

It's kinda normal at that age.
Anything you can do togheter that need done, do it. Cleaning , Cooking, meals , shopping.
See if it works to ask for help to buy your clothing, they always like a trip at the mall. Shop for the other daughter gift for bday , christmas , etc.
If you are really bored and have time to waste ask if they wanna take a trip to 'Sally' to buy some make up or hair products. Set a budget before you go
It may improve the dialogue if you take one at the time sometimes.