The Foster's pages on Wikipedia say or have said at one point that Eduardo will die a grisly death, that Bloo is Mac's only friend(not best,
only), that Frankie is named after Frank Black of alternative-rock band
The Pixies, that Mac's Mom and her IF would show up in "Good Wilt Hunting", etc...
Yeah, I'd say it's just a bunch of nonsense.
I like Duchess. Not as a person, of course, but as a character. She's a great villain figure, and I wouldn't mind seeing her given another starring role in the same quality as "Duchess of Wails". I especially like the interactions between her and Frankie.
The opening minute of DOW with Duchess and Frankie arguing was infinitely more funny and entertaining than all twenty-one minutes of the episode that preceded it in premiere airdate.