Both of these situations seem pretty simple to me.
In the second example, every other player relinquished any claim to the pot, so it all goes back to the person buying the button. The only argument I can envision is the claim that he is now on the button and never paid the blinds. But he DID pay the blinds. Complainers have no right to complain since they had the option to play the hand.
Similarly in the first example, since everyone else relinquished any claim to the pot, including the player who posted the extra SB, it should be up to the two players who strike the deal to chop what to do with the extra SB. (If I was one of those players, I'd suggest giving it to the dealer).
On a side note, I like your use of the term "surrender the SB". I've never heard it phrased that way, but that certainly helps my argument. He surrendered it, and when he folded, he also surrendered any other claim to the pot.