Hello Mum of Three! I also have a 15 week old, he was born a day before your little one. I am having the same problem with the swaddle as he wants to suck on his fist all the time too. I don't believe he is teething yet, I'm not sure I am ready for it
I want to stop swaddling because he seems to fight it so much and he also gets him arms loose but not all the way out and that just seems to make him mad! I have purchased special swaddle blankets, first the miracle blanket which was awesome but he has grown too big for it, and now the kiddopotomus swaddle but he busts out of it. I have tried to leave an arm out because he wants to suck on his fist so bad but then he doesn't sleep worth a darn. So I have a baby who resists being swaddled but can't seem to settle without it. I am going to give the aussie swaddle a try because it seems he won't be able to get out if it and I can position his fists up by his face. Hopefully it will be a good compromise. I think the days of me keeping his arms down by his sides are over :oops: The minute I unswaddle him in the morning, just like your little one, he stretches so big and it's almost like there is a magnet in his hands and they are drawn right to his mouth!
As for the feeding, I am now feeding my ds every four hours. I offer him 8 oz. at each feed. He usually eats it all in the morning, but the amount varies with the other bottles. Usually, he ends up with about 25-32 ounces a day. He gets four bottles and a dreamfeed. I only offer 4 oz. at the dreamfeed because I want to phase it out at some point. He was eating every three hours but then started to not finish bottles. So I began to offer more and spread out the time period, and it seems like just overnight he transitioned to the 4-hour easy. We are still working on naps, but that is another story.... :?
Hope this helps. I am going to try and figure out the aussie swaddle tonight, so I will let you know if it helps the situation!