Marnie sits next to 5 phonetic neighbors — Barnie, Harney, and Marney are the closest matches by sound. Most share Marnie's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"star of the sea"
"port, harbor"
"strong, manly (feminine adaptation)"
"noble birth, well-born class"
"close to God, beloved"
"surname place name"
"from the forest, woodland"
"golden thread, brocade"
"pearl"
"thinking of men, mindful of men"
"river mouth, coastal inlet"
"little one who is loved"
"delicate, dainty, languishing"
"son of Maud (Matthew/Matilda)"
"warrior of God, strong one of God"
"free, from the lake"
"of the clan of Bricius"
"little king, royal one"
"fair of face (alternate Scottish interpretation)"
"ewe (from Rae/Rachel) + meadow (from Lee)"
Similar sound: These names share phonetic patterns with Marnie — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin/Hebrew origins, giving them the same cultural heritage as Marnie.
Rhythm: Marnie is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.