I'd like to see a transcript of these kid's statements...they seem very inconsistent to me.
And, IMHO, part of the inconsistency may very well be due to the amount of alcohol in their systems at that time of the night.
Regardless, things are not adding up.
Maybe some of the inconsistencies are coming up because kids are trying to hide some of the things they did themselves. Not that they had anything at all to do with the crime but maybe they were partying so much themselves they weren't as observant as they should have been and maybe missed some warning signs.