I would suggest that the largest factor for those night wakes is lack of daytime sleep.
The time of bedtime only becomes relevant when you have a baby mostly sleeping through until morning. If you have a baby, like yours, having frequent wake ups in the night then really baby just wants as much sleep as possible, so nothing wrong with an earlier night.
Having said that, with a view to the longer term, you might want to move his routine to accommodate a later bedtime anyway, since once he is sleeping better at night, 11h would be a reasonable expectation so a 6.30pm bedtime would mean 5.30am wake is not unreasonable.
Having a dummy is great. Can baby put it in himself? You can practice this by doing things like handing him the dummy in his hand, for him to put in mouth himself. Put dummy on floor to get him to pick it up then put it in. Put dummy in his hand the wrong way around (holding the teat etc) so he has to turn it around before putting it in. Put on floor out of reach, wrong way around, behind him etc - so he has to move to get it, and turn it over before putting it in.
Also, put in place things to help him find a lost dummy in the night. Babies who can easily put their own dummy in may struggle to search for a lost dummy in the dark. I used to sew a ribbon on the sleeping bag with a press stud at the end for the dummy.
Daytime sleeps is ultimately what will do it though. With 40 minute naps, you need to make naps very frequent to stop baby getting over tired. I would say 60-90 minutes awake time between one nap and the next.
I appreciate you have a toddler too. Could you limit activities to specific times of the day. For example have mornings - 9am-12pm as toddler activity time every day and then establish that from lunchtime to bedtime every day will be playing at home, so baby can sleep better in the afternoons.