These jeans are made to order and have a TAT of up to 15 days although they’re usually done sooner.
Brand/wash/style of denim will vary — Sizes 12/18 months-5T have an adjustable waist. Size 0/3, 3/6 & 6/12 months may have an elastic waist depending on what denim is available. I try to always use ON brand denim.
If your child is inbetween sizes I recommend sizing up for longer wear.