I was back to pre preggy weight within 2 months, I'm not sure if it was to do with the breastfeeding because I spent the whole time I was bfing stuffing my face like crazy. I use to drink lots of milo as well, I found it made the night feeds a bit more bareable if I had a nice hot drink (was the middle of winter).
With the dummy I would put him to bed without and then if he needs it give it to him. Spencer was quite random with his dummy, he would have it to calm down but then wouldn't sleep with it (would fall asleep and it would fall out but he wouldn't mind) and he never had it for night sleeps only day ones

At around 2-3 months he dropped it entirely when he found his fingers.