This is true, but I wish to holy HELL they would get over this incestuous, 'small-universe' syndrome. There is NO NEED for Sam Kirk (of any rank), M'Benga, Uhura, Chapel, or Robert April to appear on this show in any way, shape, or form. All it is is a mild form of fan service that creates more irritation than anything else (especially with me). Star Wars is the worst with this crap, to be fair.
You could have exactly the same actors in these roles with different names, and it would clear up all canon issues AND allow them the freedom to develop new characters in whatever direction they wish to take them. But... nope.
Also, shouldn't Samuel Kirk be a lieutenant commander or a full commander at this point? JT Kirk is either in the academy or just commissioned himself, isn't he?