Let them fuss was what my thoughts were. It is so hard and just grates on my nerves some days to hear dd in there just fussin away, but ultimately that is what she sometimes NEEDS to do to comfort herself. If he needs you, he will let you know don't worry. I never go to dd unless it is the "MOM, I NEED YOUUUUU!!!!!!!!!!" cry if she is supposed to be sleeping. Now, if it is time to be awake, and has woken from a nap at the proper time and is just fussing, that's ok because it is time to be up - I go ahead and get her up, but it's a different matter if it is sleep time. I do my best not to let her cry it out, because that is just heart breaking, but I do let her do her fair share of "fussing". DH still thinks I am letting her just scream alone, but he just isn't around when the "MOM, I NEED YOU" type cries happen, so he doesn't know the difference like I do. Hope that helps a bit!
Do you think that he may be addicted to his paci? Some babies get addicted and constantly have to be "replugged" because they can't do it themselves, and can't sleep without it. No experience here, dd wouldn't ever take a paci (which now I am thankful for).
I wouldn't wean the swaddle yet either. If it is helping the sleep, then I would make sure he knows how to self soothe and get this routine hammered out before tackling that just yet. Also once we got dd on a really good EASY, the NW disappeared all on its own -she'd been doing 1nw between 4-5am. But, this was also when she was about 9wks old, so the habit may be a bit more ingrained in your dh. I think Melissa is right. For right now I would 1) work on getting him on a good EASY (we were pretty strict in the beginning and treated it more like a schedule instead of a routine at first till we got going well), then 2) Work on the night wakings - you can try a few different things - if he eats at the same time every night you can sort of treat it like a DF and a W2S where you just get him up 30min earlier than usual and feed an ounce less than usual every few days till you drop it - doing it gradually can help him replace those night calories with daytime calories. Or you can do cold turkey and do pu/pd or pat/shh to get him back to sleep still - your choice. then 3) once everything has calmed down I would work on the swaddle! hope that helps, and good luck!