What is his temperament like? If he is angel or textbook you might be able to get away with pushing to 2 naps and riding out any OT that might result. But if he is touchy or spirited, it's probably better to take it slow and do some 2 and some 3 nap days until he's more consistent. I wouldn't purposely wake him from the pm nap, rather if he wakes early do a CN, and if he takes a long pm nap do an early bedtime.
My DS started flat our refusing the CN at 7mos so we dropped it cold turkey then, even though his other naps weren't great and he wasn't ready. But because he is textbook I was just able to power through it until the rest of him caught up.
IMO 5:30 is too early of a bedtime. I always tried for 6:30 at the earliest, but even 6 would be doable on a really crazy day.
We 'half-swaddled' until 8mos, that is arms free and swaddled from the legs down. I really did feel it helped DS sleep better otherwise he was kicking himself all over the place. If you're unsure as to whether or not to keep the swaddle you could always try posting on the props board and seeing what other moms might have to say.
That 9:30 NWing could have been OT, it's hard to say since it was only the one and he settled easily. Could have just been a fluke?
