That's weird that it can't be taught Confuse Ray, is there move relearners in Black and White the teach moves that the pokemon have forgotten? Because there should be (in Mistralton City) so you should just be able to go there and teach it Confuse Ray no problem.
1) I don't know because Serebii says where it can be found, but it doesn't say what level it is found at, but a message board says Level 15 so if that's true, it will have the moves Thundershock, Confuse Ray, Uproar, Double Team.
2) Yes, the wild Rotom (that is found extremely rarely inside a trash can on tuesdays only!) will all have the same move sets if found at the same level. However, tons of people (including me!) are breeding Rotoms and releasing them on Wonder Trade, so if you get one that way (which frankly is going to be far more likely!) it will ahve the moves Astonish, Thunderwave, Thundershock and Confuse Ray at level 1.
3) You don't catch the appliance Rotoms, you catch normal Rotoms and have them interact with appliances found in boxes in Prof. Sycamore's lab. You can have multiple Rotoms and select which one interacts with which appliance and get all 5.
4) Since your normal Rotom is ghost and electric types, you should have a ghost move on their too.
