Coastal Pine?

I've got Falas+thôn. Falathón? The vowel length would reduce, right?

With no way to know what sea is in Nandorin I suppose there's no way to translate it. Is it possible a Nandor elf would keep the sound galad despite it having a different meaning in Sindarin?

I suppose you could, just be aware of how the name would end up being (mis)interpreted.