Reading through your posts of what the week has been like, I'm not 100% clear on what your routine is like or what you are aiming for. But, I think that may be part of the problem. I noticed one day you gave him a one hour morning nap and then woke him, which I don't really understand....if you are going for a short morning nap then that's too long and if you're going for a long morning nap, then not sure why you woke him?
I think that 4.5 h A time is a tad high for his age, but I have never been shy about saying that I feel 12 month olds on one nap are the rare exception, rather than normal. To be, 16-17 months is the age when an average baby drops to one nap and unless your LO has been consistently happy on very high A times most of his life then he's not ready for one nap at 12 months. But, if you are pushing him to 4.5 h A then only expect one nap.
Either way, whatever you are doing I think you are not sticking to it long enough. If you're going to push to 4.5 h of A time, then do it, put him down for his nap, help him get through the jolts if he needs that, or shh pat him back to sleep if he wakes early, or whatever it is that you do that works. If not, then get him up and early to bed. And tomorrow do the same! Often it takes LOs a while to learn that there is only one opportunity to nap in the day and for that nap to extend.
Either that or do a one nap day and a two nap day, but keep the one nap days the same and the two nap days the same. If you are fudging around with A times and trying 3h one day and then 4h the next and so on, then the lack of consistency doesn't help LO to set biorhythms.
And, 6-7h A time at 12 months and getting chatting in the cot is NOT NOT NOT from being UT. OT often shows up as happy, giddy, giggly as well.
To me, Caleb sounds OT on even 4.5 hours.