Upgrading your Playstation 4 HDD is pretty easy. The trickiest piece is really making sure you find the correct FW upgrade file on Sony's website. I went big on it though and upgraded to a solid state drive and it is totally brilliant. Different games respond differently but I would say on average load times are cut by about 1/3rd.. I thought it would be most noticeable on games like GTA V where initial boot up goes from about 1.5minutes to under a minute but weirdly it's more satisfying on games like FIFA where things like hospitality settings and menu selection becomes instantaneous. That all said is it's so pricey(320 euro for a 1TB SDD roughly) it is hard to recommend to anyone but I love it.
The Kaos Trap situation is totally mad. Wallop as a Trap Master isn't much better. Basically what happens is you buy a tray/box of Traps or Trap Masters but there is only 1 in 12 that are Kaos or Wallop respectively. There are multiple of the other characters of traps. This of course makes them more rare and drives demand and unfortunately some Christmas disappointment. We are so sorry for anybody who doesn't get their traps or masters in time for Christmas.