His 2 top molars are coming in and his top canine. But wouldn't he be waking more if it was that?
Not necessarily. He comes into a lighter stage of sleep at that time in the morning and likely notices the discomfort of the teeth more, and molars and canines tend to be the worst for that.
His routine looks really good. Before cutting the nap, I would try to rule out teeth if possible. Have you been medicating at all? I think it's worth a try to give meds at the 4 am waking to see if that helps him sleep through the 6 waking. Or, you could try a dream med and give it around 3am, in the hopes that he doesn't wake at all. It's like a dream feed, where you go in and just squirt the meds in without actually waking him.
As for routine with the EW, I'd try for about the same A, maybe a tish more if you think he can make it, let him sleep his normal nap and then get as close to BT as you think you can, likely bringing it forward by 30 min or so.
