I was wondering if theres anyway to appear 'insert status here' to just a particular person. Blocking is rude so its not an option but i wanna appear busy to this person so yeah if u guys know if its possible and how to do it pls gimme yr thoughts thx

Not possible. You can only have 1 status for all your contacts (not taking blocking someone in account), that's how the Messenger protocol works and no plugin or addon can change that.