The EV on unprotected picks is not measured that way in a trade at all. Its not likely enough, but you have to measure the "mystery box" value. Its the same with prospects.... trade value isn't measured by some actuary on a spreadsheet. They are speculative stocks.
You might be surprised with how speculative stocks and assets are measured lol.
I'm including everything in that expected value calculation, the whole thing is the mystery box. Yes that includes the random chance one of those picks becomes the #1 pick and the #1 pick is good. It also includes the random chance it's the 25th pick and the 25th pick ends up sucking. You measure expected value based on some kind of utility. Now, I'm just throwing out a number, but it informed based on history. I should probably not call it a calculation, but more of a guestimation. Feel free to argue against this and provide a different guestimation. But if you have two unprotected draft picks, the expected utility I would reasonably expect to get is about the same as one player who makes it past their rookie deal.