Hi,
It seems to me that your baby is about to go through a lot of changes, i.e: 3 bottles a day, 2 to 1 nap, walking, teething, etc.
For us, that age was the mark when the toddlerhood nightmare started. The first thing we had to adjust was from2 naps to one. But by looking at your schedule, it seems to me that you might want to try increasing awake time first. By that age my ds (and almost all the kids i know his age) were holding as of 3.5 to 4 hours for the first nap. Whenever ds wanted to adjust his awake time i knew it because it was arow of wakings with screaming from hell.
Whenever he wakes happy, i know it's the right schedule for a while.
Also you don't mention about teething. You say that he acts hungry, could it be he has itchy gums? why don't you try some oraljel and tylenol before each nap or bedtime?
The early wakings might be caused because he's overtired and is not getting deep sleep cycles do to exhausting days of screaming and not napping. So let's focus first on fixing his naps and then cross fingers for him to fix the early waking... if not, we'll think of something.
Have you noticed any developmental changes? like is he standing in the crib? is he walking or trying to? many babies at that age learn how to stand and do that while sleeping. THen they wake and have no idea how did they get there, freak out and hence the screaming. So putting him down after the waking with some shs and reassurance (but being really boring, you know, no eye contact or talking) might help you to extend the nap or getting him back to sleep.
So i guess the advice will go with many changes: increase awake time for morning nap, preventive meds for pain and pd and shsing for extending nap and getting himback to sleep at nights.
I really hope you find some of this helpful. We're here for you.
Welcome to toddlerhood!