This is going to be long as there are so many issues we have to deal with. Maybe I'll bullet each point.
DS2 is 4mo, and his sleep has turned to shit, basically. From birth he used to wake once for a feed around 3am which was ok, felt manageable. Always slept in his cot.
Moved him into his own room at around 3mo, trouble is it's the attic room and is freezing. I've been layering him up to make sure he's not cold but he's been waking loads recently so he might well be chilly. Where we're all sleeping is a whole different issue - DH is talking about bringing DS2's cot back into our room. Seems like a backwards step to me though.
DS1 is 3yo and up until the beginning of this year woke around 5am. He hasn't done this for some time, but I'm very worried that DS2's cries might wake him, so any time from about 4am I will do anything to get DS2 back to sleep to avoid this - 'anything' includes bringing him into our bed and cuddling him, which does send him back to sleep.
He loves sleeping in our bed, and I used to just put him between us in the bed, but have discovered DH cuddles him, which he now comes to expect - I cannot sleep this way.
DS2 has a dummy, and has, in the past week or 10 days, become completely dependent on it. He needs it putting back in multiple times in the night - from 1am through to morning. I would be quite happy to find a way to ditch it.
DS2 is ff, and I recently changed his milk from normal no1 milk to hungry milk in an effort to stave off weaning. He is a big baby - 9lb 8 at birth, and 18 2 now. I suspect it might be irritating his tummy, which may be contributing to the night waking perhaps? The hungry milk has not prevented weaning as for the past two days DS2 has pinched food from us and so I've given in and given him a bit of apple puree (REALLY didn't want to do this as a. he's 21 weeks, and b. I did BLW with DS1 at 24 weeks but he was a much smaller baby and was quite happy to wait that long).
Naps - had recently been trying to follow a vaguely Gina-esque routine of naps at 9am (30 mins), 12 (2 hours) and a catnap between 4-5pm. DS2 wakes after 30 minutes without fail, and naps in the pram only. So when he wakes I put the dummy back in and rock him till he goes off again. Was concerned that 2.5-3hours naps wasn't enough and was potentially damaging night sleep, so yesterday I got him to sleep for 4.5 hours. Last night's sleep was the same, but he was up and ready for the day at 6.30am when he's often still asleep at gone 7 (albeit in our bed).
DH is of the mindset that anything that gets you through the night is fine, but I don't want DS2 in our bed, and I don't want to be replacing the effing dummy every 30mins/1hr through the night. That's absurd. I'd rather deal with it now.
So many bad sleep associations and other issues to deal with! I really don't know where to start. Can anyone help?