I think the caution here has to be that Myers is a not uncommon German-Jewish name, but unfortunately also a not-uncommon non-Jewish name - so, for example when I see a Christian Myers, I would be cautious about thinking he would be Jewish, even if was from Germany! There were, for example, German Hammersons out in Texas in the 19th century, but they were very Protestant!
Somewhere in my now-burgeoning file I do have a note of Charles Myers' Crimea medal, and will hunt it out. I have at least found the note from the Australian researcher who was helping me, stating that she had found his Crimean War records, serving on HMS Cossack and receiving the Baltic Medal.
But, as we seem to be querying both the 43rd man and the Waikato man, could it possibly be the same person? I don't know the chronology of the Maori Wars, but could he have come over with the 43rd, fought at Gate Pa and Te Ranga (which I believe were in 1864) with them, then received his discharge, gone to civilian life (and then called Ellen and his sons to come from England, arriving on the Matoaka on 3rd January 1865) and joined the 3rd Waikato? A man with regular army experience would presumably have been a valuable asset to a militia unit. Again, the linch-pin to this seems to be Ellen - surely, however many Charles Myers we are dealing with here (and hopefully no more than two!), there must be a limited number who were married to an Ellen?
Michael