Learn English – “You are welcome” or “You are welcomed” or “You welcome”

They are both correct, but the sense is a little different. In the first one 'welcome' is being used as an adjective. The second one is a passive construction--'feedback is welcomed (by us)'. Even though they mean basically the same thing, I like the first one better. The active voice is simpler and sounds stronger.

‘Dignitary’ is what I most commonly encounter, usually as ‘foreign dignitary’. As Sam says, this is mainly used for people who are in some official sense representing their country -- diplomats, ministers, high-ranking civil servants and the like.

Otherwise, I'd say the foreignity and esteem should be obvious from the rest of the story, and simply use the word ‘guest’. Make the official esteem clear by mentioning who is the host: ‘guest’ or ‘guest of the government’, or ‘guest of the royal house’, or ‘official guest’ --- that sort of thing. Or drop words like ‘official visit’ and ‘welcomed with égards’.