I only know of one other person who has AJ’s dad as originally part of the Orange Family. I always felt that the Apples were always rather matriarchal. So to me at least it would make more sense that the Mom was the Apple rather than the Dad. Its hard to say how ponies deal with marriage, who takes who’s name, if there is a name to be shared. I say its the guy marrying into the girls family considering the immortal princess deal going on. Tends to color ones perception a bit wouldn’t you think?
 
Anyway their names are Apple Cider, and Orange Juice. Might get more of them later.