Wanda and Lorna having a few lines is most important as they are the most high profile sisters of Marvel who have virtually no on pannel relationship. Because of that at least fans and other writers getting a brief glimpse of them interacting matters alot toward any potental future interaction between them and it mentally opens up doors for people regarding what their relationship could be like if it was developed more.
Obviously, a few lines with Magneto just reaffirming her parentage to fans would be very nice as well given this series is HoM level high profile and would do alot to convince many fans that its canon and its going to stay that way or in some cases informing fans it is canon. I am also hoping that someone at Fox is reading AvX this summer and gets the idea to have her be in XMF #2 given the two characters that matter most to her in the comics will be there and the Avengers will likely be using Wanda and Pietro in Avengers #2.
Her interacting with Quicksilver offers the least potental as they already have a pretty developed relationship from being on two teams together (X-Factor and Acolytes), but I still wouldn't mind a line or two between them if the writers can find the time. Still its not as important as her having any interaction with Wanda or Magneto.