I think there should be the ability to click a "Random EVs" button in the Advanced options in the Editor screen, so that the Pokemon already has 510 EVs, but they are chaotically distributed among its stats with no pattern, like a Pokemon that wasn't EV-trained.
I'm not sure how best to actually code this, but my idea was that maybe you can have a for loop that runs 510 times and assigns each EV point to a random stat that is less than 252. Another way of doing it is to add small random numbers to random stats until the total is 510 (chopping it off there) while making sure no stats are greater than 252, as that might result in a more chaotic distribution similar to how you might constantly battle Pokemon that give a lot of the same EVs without trying.