Your biggest problem may be getting a studio - December is a popular time and availability may already be limited. Tre to decide before May and then find someone to book for you. You may have a very difficult time after the 7 month window opens - lots of people want to stay at the BWV in december.
You can request that a studio and 1 bedroom be near each other - it's certainly possible (assuming you have the same categories reserved), but it will just depend on the situation the room assigner has when it comes time to make assignments. It's been my experience that BWV preassigns rooms during the busy periods.
You may want to consider booking a 2 bedroom instead of a 1 bedroom and a studio. If interested, you'll have to see if the erson you rented from is willing/able to make the change for you. All of the 2 bedrooms at BWV are lock offs, so you'll still have some privacy, even if you book the 2 bedroom. It's less expensive than booking the rooms separately. Again, you need to decide soon and get it done before the 7 month window opens to have the best chance of getting what you want.
BWV has 3 booking categories - Standard View; Preferred View -Pool/Garden; and Preferred View - Boardwalk view. If you have either SV or PV-BW view, the chances of booking a studio for your dates in those categories is very small.
Best wishes -