Stem-nesting native bees (multiple genera (Ceratina, Hylaeus, Osmia, etc.))
The Lady Bird Johnson Wildflower Center flags special value to native bees and lists it as a nectar source; manzanitas are an important late-winter/early-spring nectar plant for native bees.
Eastern songbirds (multi-species) (multiple species (Passeriformes))
The Lady Bird Johnson Wildflower Center documents that birds consume the berries in large quantities; "Attracts: Birds." (Plotwright's generic-songbird wildlife slug is the closest existing match; common manzanita is a Western species, so the entity name reads "eastern" but the documented fruit-foraging relationship holds.)