Hi there & welcome!

He's having 3 solid meals? How long have you been doing solids for? His primary source of calorie intake should be from milk so I would be careful how much he's eating & rather do milk 1st & if you want to give solids, 1hr later. Its really though a matter of taste at this age. ALso I think your routine might need some changing. I would suggest the following routine (including milk feeds)
6.30am - wake & milk
9-10.30 - morning nap (try to stretch him to 9am - add 15mins every 3-4 days)
10.30am - wakes from nap & milk
1-2.30pm - afternoon nap
2.30pm - wakes from nap & milk
5pm - catnap
5.30-5.45 - wakes from catnap
6.30pm - milk
bedtime routine
7pm - bedtime & maybe top up milk
Pleas don't let him cio. Are you familiar with the shh/pat technique or pu/pd? If he can put himself down for naps & bedtime then he infact does know how to self settle. I think he's a little overtired especially towards the end of the day where he is awake for 3hrs before going down for the night. When they are overitred, they tend to have trouble settling at night (especially in the early hours of the morning).