You're more than welcome to keep posting here!
It looks to me like your routine is your biggest issue. He's up for too long before his 5pm nap and then up way too long before BT, so is most likely quite OT when he finally does go to sleep for the night. OT usually presents itself in one of two ways in night sleep... either a LO has lots of early NWs and unsettled sleep or crashes for the night and then wakes up early (after 8/9/10hr) and has a hard time getting back to sleep because of the built up hormones (this is your case).
With babies of this age, we typically suggest working on an 12-13hr day still, which is what your goal is with the 8:30-8:30 routine. But, if you want to do that routine, you need to do whatever you can to get him back to sleep when he wakes in the early morning. If not, I think you need to start putting him to bed earlier, i.e. 8pm, so he's getting more restful sleep and then you can start working on his routine from there. Right now, his day is super long with not a lot of restful naps in the afternoon, so he's OT.
WRT your milk supply... not all EBF babies make a full 4hr EASY until they are started on solids. Have you tried giving a top up feed an hr after the main feed, so that you know he won't wake hungry from a nap and you can also increase your supply a bit?
Hope that helps a little. What do you think?