I know this is blasphemous, but I don't think the beignets at WDW or in the park at DLR are very good, regular or seasonal. I haven't had the ones from Ralph Brennan's though. I have been to New Orleans a lot, so I am a bit of a beignet snob. Luckily, I didn't expect the ones at the parks to be good.
Also, any of the ice cream at either WDW or DLR, unless it's dole whip all pineapple which really isn't ice cream, is pretty bad. It's not Blue Bell bad, but my local grocery store chain has a better in-house brand. However, at WDW, the ice cream at Ample Hills, when it was open, in the France pavilion at Epcot, and the gelato place at Disney Springs are good. Haven't had Ghirardelli at either park; we usually just get the chocolate, which is kind of mediocre too. I am also an ice cream snob, since I worked at one in high school, where we made ice cream, and still have a high end machine at home.