Young adults these days take pics of everything. They're constantly snapping away with a cell phone or digital camera. Because there is no film, there is no cost associated with taking pictures. So there's really no limitation.
That pics were taken doesn't indicate that this was rare or unusual behavior. In fact, that may be part of the motivation. Girls kiss and act like this for attention. Getting your picture taken is a form of attention.
Where were they - they're in someone's home. In several of the pics, I can clearly see a screen mounted on a wall which is used for a projection TV. It is white with a black border and kind of resembles a whiteboard. In other pics, you can see speakers mounted on the walls. So the room they're in appears to be set up as a home theater.
It could be a basement, but I doubt this for two reasons. First, AFAIK not many homes in Florida have basements. Secondly, I can see a ceiling fan - something that probably wouldn't be needed in a basement, even in Florida. So it could be an addition or something, but is definitely a private residence.
I'm not convinced KC was on something in these pics. Plenty of girls act that way either sober or while just consuming alcohol. She did steal money and didn't work, but partying is rather expensive and she needed gas for her car. She does not appear to be anything more than an occasional recreational drug user, if even that.
Finally, see my above comments on youth & pictures. Because it is free they constantly take pics. It's to the point where it is a mindless act, something they do habitually.