Small recommendation to change the category for capital "City"s to something like 'Capital is country name plus "city"' to avoid Vatican City confusion.
Andorra la Vella means "Andorra the Town", to distinguish it from the Principality of Andorra as a whole. Although in Catalan the word vella (like French vieille) is derived from the Latin word vetula which means "old", the Vella here (like French ville and Catalan vila) is derived from the Latin word villa and means "town".
In other words, exactly the same as Guatemala City, Kuwait City, Mexico City, Panama City... these are cities/towns that have the same name as the country they are capitals of, that we attach a word to that means city merely to differentiate between the city/town and the larger country/principality. In all cases, "City," "Ciudad," "la Vella" are not originally part of the name of the place.
I dont think I would ve gotten nr7, 11, 15, 16, (atleast not without guessing, 11 perhaps by looking at the right continent..)