Now before you insta remove this without reading anything This isn't really leaking info because All this does is add a dud model into the game. The character doesn't act like Osana or anything and just stays by the lockers (or follows another studnets A.I path). Anyways So I was dicking around with character files to find out how to trigger the other fun girl defenses and I stumbled upon a way to kind of add Osana. I say kind of because all this does is add her model into the game, the thing created by doing this will look like Osana but it will just stay at the lockers and won't have her portrait. though it does have her character data. Anyways here is how you do it.
Step#1 go to the Json files where you used to Add Osana by going to yandere sim\YandereSimulator_Data\StreamingAssets\JSON and clicking student.Json.
Step#2 Copy the Data from student#33 (i.e Osana) Then remove the data from another student (student#34 Is what I use because It doesn't replace any of the normal students)
Step#3 Paste the data from student#33 into the removed students string of text and rename the student to Osana Najimi.
Step#4 Your done!. Now you can load the game and find a (glitchy) but real Osana!. On a side note if you do decide to add her by replacing another student The Osana will follow the route of the removed student. I hope this little glitch i found gives you a couple laughs and i hope you enjoy :P Oh and on another side note the Osana won't have stockings rip.
If your 2 lazy to copy the Osana code just copy this and replace a students code with this one
Actually the "Second line of defense" also checks whether you've modified any other student to look like Osana and trigger "her" - but that specific check has a bug and doesn't work (at least as of the Jan 4th build) - So yes, it works for now, but don't expect it to work in the future. Currently the only way of adding the real Osana, along with her daily routine (and the task that you can perform for her) is to modify game code. Not too difficult if you know what you're doing, though I think it's immoral to distribute that information after Yanderedev's explicitly said it's against his wishes.
I saw a youtuber that probably added Osana that way and ended up with a complete mess. As I said, Osana already has some event triggers and stuff that expect her to be student #33, any other number will give you a buggy and glitchy character.
Right now the only way to see the real Osana is to use a mod that bypasses "fun girl" but doesn't change Osana's original routine.