Sairz, there are discounted tickets available on all the Rome-Naples high speed trains departing tomorrow. December 18 is The first day of xmas holidays when all school close.
You don't actually need to wake-up in the middle of the night or in the early morning for the 17th of April, relax. Would you hurry to get train tickets 120 days in advance in your home country? Of course not and Europeans do the same.
As you have discovered, it's 120 days in advance at the minute, italian time.
There are no pickpockets on the Campania Express, not fewer, because there are no crowds, standing is forbidden, it doesn't stop in the suburbs where they usually get on and any single ticket is checked before boarding. The Campania Express is used only by foreign tourists, the conductor would spot a pickpocket miles away and would just stand by him/her during the all journey.