After drywalling, should the next step be applying primer first, or should texture be applied before primer?

Always prime before applying texture. Use a high-solids drywall primer, like USG's First Coat, to help equalize the porosity between the drywall face paper and joint compound. This step significantly reduces the risk of flashing. Avoid using PVAs prior to texturing, as they can "seal" the wall and prevent it from "breathing" while the texture dries, potentially causing pinholes or air bubbles. After applying texture, painters may choose to apply a primer before starting the paint system.