Unfortunately I don't have any links because it was spoiled over an interview/Article mix.

However, it was confirmed before that Micahs and Nikkis storylines ends in season 3 so.... is as good as confirmed because no matter how much I would wish them to just go away only to surprises with a appearance or two in other seasons, in heroes they round up storylines by killing people (or let them dissappear in time which is almost the same

). -.-
In my opinion it gets repeatitive and I hate it. Most of all since Nikki never got to do much herself over the second season (after she FINALLY found her own strenght even without her power on).
Now bring her back as another personality, no matter how good they would have planned it is really pushing it and makes the whole thing pathetic. -.-
Most of all since the sanders/hawkins family was doomed 2 seasons long and never got the chance to be happy EVER.
As about killing a kid in the television: it happened many times and in many shows as also in many movies. Nothing new there and to be honest, why should it be SUCH a problem? I mean there are so many kids that gets killed in our world through accidents, murders and much more in a daily manner.
So.... no reason to be shocked by a kid that actually does get killed as a character and not for real.
A few months ago (as example), in the series "medium" (thats the title in germany at least), the actress saw in her dreams a kid that drowned in a car accident after the car fall into a sea.
Sure I felt sorry and I wished to be there and able to get this kid out of the car (his mother was already dead through the crash), though inside me I know that this young boy (he was like 7 years old and a good actor already) is safe and sound and got payed to play that role while other kids in our real world died even more horrible deaths for real.