The two questions that come to mind so far about the not-so-set-in-stone snippets we've so far are :
1) Did Kostas have no family whatsoever? It seems strange that no relative of his was elevated to the Peerage. At least a mention of that they declined, or that had his relatives existed, they would have been ennobled, or something. It just doesn't seem like Roger to forget him.
2) The title Duke of Mars is bugging me. It's mentioned in We Few that :
The UOW was even older than the Empire of Man, having been a brief competitor for stellar dominance against the old Solarian Union. It still maintained "ownership" of Mars, some of the more habitable of the Sol System's moons, and several outworlds in Sol's vicinity—enough to retain its independence from the Empire and be officially considered the sixth interstellar polity. Its territory, however, was entirely surrounded by Imperial star systems.
So what exactly is the status of Mars? Is it UOW or Imperial territory or something in between? A brief clarification might be nice.