**SPOILERS**
So the identities of the three masked men are definitely the playboy, student council president, and homeroom teacher. The first one who’s reason in ch 2 is “love” wearing the unbuttoned shirt is the playboy. This one is the most obvious because of his strong perfume. He also shows some interest in the MC, being friendly to him despite him not being a girl. The second is the “interest” guy who’s completely naked except for the mask aka the student council president. From the pres’s perspective you can see the playboy so process of elimination. He seems to have an obsession with the playboy that he confuses for hate so, he wants to be involved with the guy his obsession has shown interest in. The third culprit who thinks the MC is “cute in love” and who wears the jacket with the brooch we see since ch 1 is the homeroom teacher, who is also responsible for luring him out to begin with. Thus the absence and the black hair in the storage room that the MC confused for his LI. You can even see from his POV when he shares his reason that he is watching the MC and his LI from the front of the classroom. Sadly none of these men are Kouki who he hoped for obviously from the ending :(
Fukumen Danshi