I'm with pianolover. I'm not criticizing the fact that you asked a question, but I think your question could have been more meaningful to you. (And I think, to some degree, this is where pianolover was coming from, also.) I've never understood why we get questions like, "Hey, so, I just learned Rachmaninoff's 3rd Piano Concerto. I think it's easy, and I play it perfectly. Can you tell me what the relative difficulty of Mary Had A Little Lamb is?"
Now, obviously I'm just being facetious to make a point, but PL is right: if you can play at that level, you should be able to look at a score and decide its relative difficulty. (Especially in conjunction with a recording/video.) If you can't, I would invest some time in studying the music to develop this ability.
Before I get long-winded on the above, I will make at least one dehurtful retraction, so you know I'm not some mean criticizer who should rot in the 9th circle of heck (yes, I typed "heck" and not the other one that automatically gets changed to "heck"--I have learned my lesson): I also believe it is perfectly fine to ask others who have played a piece what they thought of it.
So, in the context of "ranking", I'm not sure that hearing someone else's point of view would benefit you. Their rank depends on their strengths. Your rank will depend on yours. I bring it full circle by saying, it's easy to see that Mary's Little Lamb is much easier than the Rach 3. But compare La Campanella to Feux Follets? If you play intricate, fast passages well, you'd probably prefer Feux Follets. If you play octaves and leaps well, you'd probably prefer La Campanella.
What are your strengths and weaknesses? I think, perhaps, knowing that, it may give more meaning/weight to any rankings. I'm sure there are several experts on these operatic transcriptions. (Unfortunately, I am not one of them.. but knowing the answer to the question, I could certainly help analyze the scores if you'd like.) The more information they have about your abilities, the better they would be able to help you decide on a ranking that suits your technique--and, in which case, is more meaningful than a random list.