These examples are JA's (and Elizabeth's) irony at work again, I agree. I don't think that Elizabeth is in awe of Darcy, any more than she is of Lady Catherine. In fact, IMO her attitude shows self-respect. I'm thinking of another JA novel where the heroine's father and sister fawn over a distant relative who is clearly not interested in them just because she's higher on the social scale than they are.

1) As a realist, Elizabeth understands that a man like Darcy would normally never take a serious interest in her (as wife material, I mean). As a matter of fact, this is clearly borne out during his Hunsford proposal where he dwells on the disadvantages of the match.