Yes, the Third Ballade is considered to be the least difficult. The most difficult one is the Fourth.
I would say that if you can play any one of them well, you are technically capable of playing all of them. The 4th would require more dedication and time to perfect, but you would be rewarded by being able to play one of the most sublime pieces ever written.
The Chopin Ballades are sort of big enough pieces to where you wouldn't learn one just to "be able to play the others." If you have the technique to play Nos. 2 or 4, and those are the ones that you really want to learn, then learn them. If you don't have the technique for them, then learn one of the others. Talking about "musicality" is total, subjective BS; if you're just asking about technical difficulty, they're (easiest to hardest) 3-1-2-4. Anybody who says otherwise hasn't played them, period, and is just posturing. If you plan to learn them all over the next year or two, you might learn them in the 3-1-2-4 order. Otherwise, just learn whichever one you think that you understand the best, if you just can't make up your mind.
You sir are an idiot.
Why is talking about musicality and difficulty with interpretation bullshit?
The 4th is universally regarded as being the most difficult, as to truly master it, requires a great amount of musical maturity, something that is not as important in the more virtuoso works of Chopin's youth such as Ballades 1 and 2.
The 4th Ballade also presents, in my opinion, one of the greatest tests of voicing and phrasing in all of Chopin's works.
A piece all to often performed badly due to the players playing the work without the required sensitivity and maturity. Another point to consider is the nature of the 4th Ballade. This is arguably Chopin's most intimate and tender composition and to convey these emotions to the listener requires a profound level of maturity.
All these points fall under musicality, and for you to dismiss it as "bullshit" only seeks to make yourself look like an idiot.
Lastly, the double note section at the end of Ballade No 2, is not as technically difficult as the coda in Ballade No 1. So I fail to see why you rank the difficulty the way you do. In fact I would wager few professionals consider No 2, more technically demanding than No 1.
Take the 3rd. It's the easiest and the most beautiful. Seems like a nobrainer to me.
Actually, my teacher has advised me to hold off on the Ballade's until I have played a bit more of Chopin. I suggested instead an "easier" Liszt transcription and she agreed. I would still like to keep this thread going, because it is an interesting point of discussion.
I find that #4 is simply beyond perfection, really fun to play!