Percy cant use neamen lion's cape either cus percy gave it up to let grover go safely though the water body with bessie. Percy voluntarily gave up the special object and can't get it back now so I don't think he can use it any longer
Percy can't use mrs o'leary cus first of all mrs o'leary is her own beimg with her own thoughts. He can't control her. He can't even summon her. If zoë and percy happen to fight somewhere mrs o'leary is and mrs o'leary decides to help percy, it still won't be illegible for this battle because I mentioned that percy can use all powers and mrs o'leary isnt one of percy's powers nor weapon or special object.