An interesting series, especially the ones comparing lenses/composition. All are lovely pictures, beautifully shot. There's about 4 that I really love, I can't choose a favorite between them as I find they each offer something different.
As far as your same scene shot with different lenses - my personal opinion is that the one taken with the 50mm lens is the weakest of the series. I'm having a tough time explaining why - I can't quite get my head around the right words to explain what I think. First I noticed that you framed them slightly differently, with the 35 being landscape while the others are vertical. While there isn't a huge amount of difference between the 21 and 28, you made slight changes in framing which made both shots very effective - you were choosing the framing to compliment the lens' capabilities. Same with the 35, the landscape really works well there. I don't feel you took the same advantage of the 50 picture, I'm not as crazy with the framing/composition of that one.