I am the author of posts 99, 101, 102, 104, and 113. Call me Dan. I also created and posted the two vidcaps of Katey previously, disbelieving she had passed.
Regarding KateyFans group, it was the group owner who first posted of her death in that group on Jan. 24. On Jan. 26 he also posted the text of her Tumblr scheduled publish suicide note. In another post on Jan. 26, the group owner responds to a skeptical member, mentioning her date of death (DOP), Jan. 17. He also remarked that the skeptic can wait about 8 months until the coroner's inquest will be published. In addition, he mentioned there was an ongoing problem with a local stalker as the reason for the family's secrecy.
Another group member stated that he had posted what he deemed a respectful memorial to Katey and reportedly was verbally accosted by Katey's sister. I assume that member removed his memorial. It is mentioned a couple of times in the KateyFans posts re her death that her family did not approve of her internet friends and activities.
As to Facebook, there is a page titled "Remembering Kate Cooper" https://www.facebook.com/kate.cooper89 . I do not know if this was Katey's original page or not. It does show her profile pic was changed on Jan. 15.
This is all I know. If Katey has decided to disappear from the web and fake her death, it is an elaborate scheme, involving the owner of Yahoo KateyFans group, which I do not believe that he would be complicit in..
If anyone wants to find official verification of death now, the group owner suggested filing a request of death certificate with the NZ registrar of births and deaths, DOP Jan. 17 2015, Katey Cooper, Christchurch. However I believe that option is only available to NZ residents.
As for coroner's inquest, I suppose we will have to wait until around August, being 8 months.