I'll listen to the whole performance as it probably makes you understand better what Strauss was looking for. It's just that the excerpts you posted show some gloomy atmosphere very well staged and all, but I don't get where the refrain, couplets are.
I hadn't heard of The draughtman's contract, is it in the same vein as Barry Lyndon ?
Continuing on Strauss, here's the Fledermaus overture conducted by Karajan; class