I struggle between one or two perps myself. I can definitely see how both girls would co-operate with one perp if they threatened to harm the remaining girl if the other left.
There's something about Elizabeth's purse that doesn't sit well with me. Her mom said that she took her purse everywhere. It doesn't make sense that she left it by the drainage gate, and that she didn't bother to pick it up if she was lured. Was she grabbed and Lyric followed, was Elizabeth grabbed and the purse was tossed on the ground because she had a cell phone in her purse? Lyric was described by her grandmother as "a bull in a China shop", so why would she, the older, stronger, larger, more determined of the two, follow obediently if Elizabeth had been grabbed when common sense says make noise and run in the opposite direction? I understand that perhaps one would follow obediently if the other was in trouble, but Lyric would be the one to control first - I think. No one was seen dragging two girls to a vehicle, so presumably they weren't dragged to the vehicle. That suggests luring, but luring doesn't explain Elizabeth's purse being left on the ground near the bikes. Two people walking with two girls, preventing either from doing anything, explains why one person wasn't seen dragging two girls to a vehicle, and why the purse was left behind.