So, it most definitely going to be the same Kim Possible missions with slight tweaks to the mechanics, and of course different stories on the device. From what I understand, it will be mostly Major Monogram and Karl the Intern doing the talking on the device, as agent P doesn't actually talk, with the participant being brought in to assist Agent P. Some of the stuff will need to be changed (the Bebe Baby in Japan, the finale in Germany with the villian being chased around the clock).
The big difference between KP and Agent P is that KP has multiple villians, whereas Agent P has only one. So, they will have to have different stories, but again I think the actual mechanisms will mostly be unchanged. I told my DD8, who got into KP because of the world showcase adventure, and was afraid she would be sad it was going, but she like P&F also, so she finds it kind of exciting that the missions will be "new", I think we've done them all at least twice.