Kiddo is too big for size 000 but a little too small for 00. 00 has little grippy things on the feet, but says it’s 3 -6 months. Surely he’s not needing grip in the next couple of months?!
Usually they're crawling 6 to 12 months. Around 9 to 12 months they're pulling themselves up using furniture to help them stand up and from there they try a few steps. Some kids don't walk until they're 18 months old. It depends on how motivated they are. My son was highly motivated to get around and was walking before 12 months, but my daughter took longer.