Occipital bone soft spots or fontanelles with overlying soft tissue: This is a common finding in infants, where the bones of the skull have not yet fused, and the soft spots can sometimes be mistaken for lumps. The presence of these soft spots is normal and expected in infants of this age.

Benign scalp lesions (e.g., epidermal inclusion cysts, sebaceous cysts): These are common, benign growths that can appear as small, movable lumps on the scalp. They are usually non-tender and not red, fitting the description provided.
Lymph nodes: Although less common in this specific location and age group, enlarged lymph nodes can present as movable, non-tender lumps. However, their presence might indicate an underlying infection or other condition that warrants further investigation.

Neuroblastoma: Although rare, neuroblastoma can present with masses in the neck or head. Early detection is crucial for treatment outcomes, making it a "do not miss" diagnosis despite its low likelihood.
Leukemia or lymphoma: These conditions can cause lymphadenopathy (enlarged lymph nodes) that might be palpable as lumps. Given the potential severity of these conditions, they must be considered in the differential diagnosis.

Dermoid cysts: These are rare, benign cysts that can appear on the scalp. They are usually present at birth and can grow slowly over time.
Hemangiomas: Although more commonly found on the face, hemangiomas can occasionally appear on the scalp. They are benign vascular tumors that can grow rapidly during the first year of life.
Rhabdoid tumors: Extremely rare and aggressive tumors that can present as masses in various parts of the body, including the head. Their inclusion in the differential is due to their potential severity rather than likelihood.