Having discovered her ability to interact with Alexa at the beginning of the season, Alberta should have just used the "Simon says" function and told Jay Sam was in the safe. Although it is possible Alberta is not aware of this function as it's unlikely Sam or Jay felt the need to use it.
Flower touches the vault door to close it shut. This has not been established as one of her ghost powers, as Trevor is known as the ghost with the power to touch objects. Flower's power to touch things hasn't been portrayed after this.