Alexander McInnes buried at Robe was also on the Hercules. He was from Boreraig, married Maragaret McRae who died during the voyage, and joined his brother in law in what is now Naracoorte before the family settled at Crower station between Naracoorte and Robe. He had two daughters named Catherine, one married a Watson at Konetta. His only descendants (son John) have surname Murray.
Alexander McInnes from Heast who married Rachel McInnes of Harripool arrived in Adelaide and went to Wellington. Rachel died there in 1865. Alexander later married his housekeeper in Meningie and had a 2nd family. Most children in His first family went to Victoria. One daughter married an O'Dea at Tungkillo.
The two Alexanders were related. They had a younger common relative, John McInnes, who arrived in the late 1860s. John McInnes grew up in Boreraig and when about 10 moved to Heast Alexander's croft. His father took over Heast Alexander's ahre of the croft when Heast Alexander emigrated. When John emigrated, he joined Boreraig Alexander's sons in Australia.
As far as I know, noone has been able to work out exactly how any of them were related.