Oh wow, thank you for all this information—fascinating stuff, and I did not know it was this complicated! I think we're supposed to understand that Ewen owns Ardroy outright ('Ewen... had ruled his little domain'; 'Mr Cameron was apparently a landed proprietor', though that second one could easily by Keith's misinterpretation), but you're right that it's not clear. (This isn't really a side of the historical detail that Broster gets into much!).