My DS did the 13 hour day from 11 months and routine was pretty much identical to yours for a long while. (Actually at 12 months his morning nap went UP to one hour as he needed the extra sleep while he was cutting teeth).
Whether or not they do a 12 hour day or a 13 hour day will pretty much depend on their nightsleep. At this age some LOs will do a 12 hour night and others won't. If they will only do an 11 hour night no matter WHAT then you are better off to get the extra sleep in the day....otherwise you are always trying to catch up from a "short night" which was not really a short night at all. KWIM?
My LO did an 11 hour night until about 12 months and then it increased to 11.5 hours.
The cryouts at 430ish can be from a LOT of different things. At that time of day (usually between 430 - 530) hormone levels drop as does your body temperature. The melatonin that regulates sleep is at it's lowest point. It is a very common time for babies (and adults!) to start moving into a lighter phase of sleep. For adults we can often roll over and look at the clock and groan and go back to sleep - but sometimes we end up lying awake until a moment before the alarm goes off, right? LOs are the same way....if all is perfect for them (still tired, not OT or UT, perfect temperature with the bedroom not too hot and not too cold, diaper not wet, lovey in hand perfectly, no pain from teeth, no tummy aches, no missing mommy, no hearing the cat meow) and so on, then LO can just roll over and go back to sleep. But one thing not quite right....and LO is wide awake shouting for mommy. I'm sure that some LOs are more sensitive and particular than others, too! We have an ongoing battle in our house, DH wakes and needs to go to the bathroom at 5am ish and always wakes DS when he gets up. But he insists that he heard DS waking and that is what woke HIM up in the first place...chicken and egg.
Also, going back to your routine -- you said in the morning nap from 940 - 1020/5ish that he wakes, but you would not let him sleep longer than this anyway. You are right with this. He is waking at 40/45 minutes as he was UT, which is exactly what you want for this morning nap at this point in 2-1. If you pushed him to the point where he was properly tired and then woke him from that 45 minute nap, it's messing up his whole day as he is spending it just waiting for that nap, and if you get afternoon nap time wrong then you are starting a nasty OT game. So what you are doing NOW is perfect!!!
And, merely for reference if you are interested, what I did was to KEEP that morning nap at 930/940 right through until DS refused it at 14/15 months. I just kept cutting it shorter, but always kept it at the same time. Luxury of SAHM life was part of it, but I started getting my days REALLY routine....up, milk, dressed, bkfst, out for walk or play outside, etc. Back in the house, into pyjamas, books and nap. The set nap worked SO well for my DS, and keeping the day in a very sorted order helped him know what was coming next. He kept his nap from 145/200 to 4ish for a while, and when it started getting to only a 1.5 hour nap consistently (so a few days in a row, not a one-off) then I cut the morning to 30 minutes from 930-1000 and nap time moved up to 100. Worked well for us!
