That's a bit over ambitious to start with, yes! It's more a skill for the handler to learn than for the animal.
As for slippers, be careful there - you may end up with a dog that's going to gnaw on slippers at every opportunity because you're rewarded mouthing a slipper! Putting the behaviour on cue and then letting it stop happen un-cued is the very hardest part of this, and usually never works completely, so be sure you don't teach them anything that you will mind occasionally being offered when you don't ask.
For instance, I taught my horse to pick up a towel with his mouth and shake it around, and he now gleefully picks up every coat, towel, saddlecloth and other fabric item that is hanging over the railing, in the hope that it sets off the treat machine
