Yes, but I don't believe CG have carte blanche to release non-canon characters. It'd very much depend on whether Disney are willing to allow Prince Xizor in or not.
I'm not the most 'up' on Star Wars lore. However, it felt to me that he was very much shoe-horned into books, to give the heroes a foil. Time-line wise his appearance and disappearance are all very convenient as to not interfere with anything canon.
It felt to me that Thrawn in a lot of ways replaced Xizor in canon. They made the green guy a blue guy. Both of which went against the norm of humans (upper-class) generally playing the Imperial humans.