Stabilizing and planting on a steep sandy slope

This site lists a technique of using check logs to terrace by building up rather than digging in:
https://www.tenthacrefarm.com/2014/10/heres-a-quick-way-to-terrace-a-hill/ 

Here are some plants for erosion control:
https://wshg.net/blog/2014-06-17/best-native-plants-for-protecting-your-hillside-from-erosion/

PNW options: (definitely full sun, southern exposure, drier soils)
https://wmswcd.org/wp-content/uploads/2015/12/Native-Plants-for-Erosion-Control.pdf

Some promising ideas: Kinnikinnick, deltoid balsamroot, Red flowering Currant, Hairy Honeysuckle