I've wondered quite often about a copycat. It's the only other possibility that fits my theory of the date reversal, if the killer was not the same for both sets of girls.
I agree with you too completely about MJK. I followed Lizzie & Lyric's case very closely and he was absolutely my first choice. Still on the fence even today because he so closely fits the puzzle as the missing piece.
In fact, I was shocked when he was ruled out by LE. Like you, I too wish I knew why...
ETA: By the way, so glad you're here. Really enjoy your posts! Good to know you have 'your orange lamp on.'