My sister in law usually has us over for dinner on christmas. We have been trying to figure out if she wants us to come or not so we can plan our holiday accordingly. Now my parents would like to see us for part of the day (they dont care when and will work around our schedule). But its getting to the wire and i dont want my parents being left in the dark for much longer. Also I need to make plans with my one sons father (who is really being great and also letting me wait till i know whats going on with my sister in law). What can i do to get an answer out of her? Weve already flat out asked her what she would like to do.

I suggested to my husband we spend the day at my parents then my son can go to his fathers christmas ening/nightish and we can tell his sister were free all day christmas eve if shed like to do something. He said he hated this idea and needs to see his nieces on christmas. (okay i can get that)

Also inviting them to our house is out of the question as "they perfer not to travel with the entire family" (theres five of them)

How should I solve this so all are happy?
Its hard to make plans because my husband refuse to agree to do anythign with anyone else til he knows when he can see his sister and nieces.