E.S.
I have spoiled ones too..my fault, I would buy a lot of stuff earlier in her life. So did grandmas and aunts and uncles and etc. etc.
I have two suggestions that may help.. instead of toys/presents as rewards, have it be an experience..my girls reward charts have "prizes" that are not something that can be bought in stores so much as things like.. go to the zoo, go to the park, go to the ice cream store, get your nails done, get your hair done, etc. If you were buying them dollar store toys, you may have to revamp the # of stickers to get a prize that may cost more money..(you could always go to the free zoo too)
My other suggestion is something that I had to do with my own kids.. either do not take them shopping with me (which is hard) or NEVER buy them anything when they are with me. The key is to be consistent. I mean NEVER. If they ask for something once and you buy it, then they will keep asking and have a breakdown. If you think it is cute and something that they should have as a reward, buy it when they aren't with you and put it away somewhere for them to get when they are good. I have a secret closet for toys that I will pull out on a rainy day IF THEY DESERVE THEM!! The asking won't stop, but the tantrums should. My girls still ask for stuff at stores -- anything from fruit snacks with princesses on them at the grocery store to toys/outfits at a mall. My answer is always a consistent no. Sometimes just no. Sometimes "ask Santa" or "ask the easter bunny" or you get presents on your birthday. etc. I really haven't seen a full blown tantrum about not getting something at a store in over a year since I started this.
As for sleeping, this is extreme, but for my oldest I literally had to lock her in her room. My problem was a little different than yours though.. when she came out of her room in the middle of the night she did it quietly (sneakily) so we wouldn't wake up and then she would go wreak havok on the house..., trying to make a grilled cheese to trying to take a bath. I couldn't chance her getting hurt so I had a hook and eye put on the outside of her door. Also giving her a night light helped..not the plug in kind but there are these kinds that they hold on to. I only had to do this with my oldest and only for about 3-4 months (I might have been able to stop earlier, I'm really not sure) until she learned that she had to stay in there. Like I said, I think this is extreme but if all else fails..