"I love Hori-san, but she's in love with you, so I'd like to get rid of her rival Nishida-san at least"
That makes...literally no sense? If that were to be the presumed scenario:
1. Why would Fukuoka be helping his own rival?
2. How would getting rid of Nishida benefit Fukuoka in any way, when all it would do is help drive Hori towards Kitajima? It would make more sense for him to support Nishida.
3. If this doesn't help Fukuoka in any way, why would Kitajima agree to a hella suspicious plan that only benefits him and not the guy proposing it who claims to be your love rival?