Finally, Walter KERR's birth certificate arrived (actually it was pretty quick...it just *felt* like months) and I was right! A major triumph And you were right as well.
Walter, born Remuera in 1860, was the son of William KERR of Moffat, Dumfries-shire, and Ann Mary Morley of Harrogate, WYS. William left Scotland with his brothers John Bell and Robert sometime before the 1841 census and all three are found in Halifax at that time. William & Ann married in 1853 in Knaresborough and emigrated in 1859, arriving in December aboard the Shalimar.
A surprise...listed on Walter's birth cert is Frances Morley, a witness. I believe she was Ann's sister, who apparently arrived with her parents and another sister in March 1860, on board Blue Jacket. I'd been wondering why Ann, who lived in Ramarama, would be giving birth in Remuera. Apparently her family lived there.
So many thanks to everyone who helped out with my search! I chewed over every suggestion.