Having trouble. How to fix these minor problems so my twins's can have toddler beds instead of cribs?

Ok. Now obviously I want to switch my twin's cribs into toddler beds. Ok now Johnny has a 4 in 1 crib so I can easily switch it to a toddler bed with little rails on the side. But Sammy (Samantha) has only a 3 in 1 so she doesn't have the rails. I tried one of those rail things for kids that sleep on normal beds but it doest work because there has to be a box spring under the normal mattress for it to stay. Without it, my kids pull it out and leave it hanging. Also Johnny likes to pull out the night light and put it back in several times. My daughter Sammy pulls out the plastic outlet cover things (white or clear doesn't matter) and she chews on them. They also pull any cords out of the wall so I have to make sure that they can't reach their lamps' cords by putting the lamp on a shelf on the wall and placing a dresser in front of the cord. The reason I don't put the lamp on the dresser is because Johnny will stand on whatever toy he can (no matter how small) and turn the lamp on and off. He also used to turn the lightswitches on and off until I took the lightbulbs out of the ceiling lights in both of their rooms. I told you I need help. No matter how many times they get ed and put in timeout they still do all of this behind my back. I need to be able to allow them to have toddler beds because they wiill be 3 soon and they don't know how to climb in or out of their cribs and they scream in the morning because they want out to play. So how in the world do I fix up their rooms and Sammy's bed so I don't have to worry about them getting hurt or messing with stuff at nap, bedtime, or when they play in their rooms?