Hmmmmmm. Wwwwell, that stretching-the-front-leg behavior sounds more like socialization stage to me though it's hard to say without a video. The pleo will stretch its legs one after the other and lean forward on one front leg as if to take a step and then suddenly pull back as if they don't want to take a step. They don't do much moving other than wagging their tail, raising their heads up and looking from left to right while blinking their eyes and sniffing, and doing the leg-stretching behavior. Your pleo may just be very young still. Honestly I thought given how long it sat around that it would still age up if they weren't played with but... I'm not sure. Ryu stayed in socialization stage for ever. I was so bored with her I wanted to do some modification to push her through it but one day, she just started walking. I'm sorry to say that if feeding/increasing light/checking for injuries has produced nothing and you don't feel comfortable modifying her, you're just going to have to play with her the way she is until she moves into juvinile stage. When your pleo does decide to walk, don't be alarmed if they start walking backwards. They walk backward first for some odd reason. If this isn't what she's doing, we may still need a video when you're able to take one.
Talon