I think there will still be X-Men packs in the store, but honestly I would use a Tier-2 ticket on her and save the x-genes for her uniform. It's a nice boost.
As for your second question, the short answer is no. The long answer is:
X-23 is one of a select group of characters who can go to level 70. Once she is Tier-2, you can use her in World Boss or World Boss Ultimate to enhance her potential. Potential will show up as a little bar where your Advancement button currently is. You will probably have to do this several days, as it's very rare to get 100% with just one run. But once you have 100%, you will be able to realize her potential and then it's a series of stairs: feed her bios from anyone to get her up two levels and use phoenix feathers and m-kraan crystals and gold to unlock the next two levels. Her gears will be upgraded with phoenix feathers and materials from WBU.
Hope this helps, feel free to contact me if you need anything else.