He would have been overtired by bedtime because of that last nap he missed and when they get overtired, they can have a rough time transitioning between sleep cycles, they tend to wake up more and take a long time to settle. So I think that might have been the case as 3 hrs for a 14wo is quiet a long time to be awake for. You're right in that some foods can cause them discomfort so maybe try and stay away from the foods you "think" might be causing him discomfort.
With regards to the last nap/catnap, what were the other 2 naps like? I remember there was a time when I had to limit dd's 1st and 2nd nap to just 1.5hrs so that there was enough "drive" for her to take the catnap. Oh and don't be afraid to AP the catnap... this nap will be the first to disappear and most mums (myself included) do this nap in the stroller/baby carrier/arms/swing... I did the last nap mostly in the baby carrier/sling just to give her and I a little break from the shh/patting and to be able to get things done! If he does happen to miss this nap again, I would be tempted to put him to bed even earlier, maybe even 5.30pm (I've done bedtime as early as 5pm!) to avoid him from getting too overtired by bedtime.
With regards to shh/pat vs pu/pd. I did mostly shh/pat (and still do if need be) as pu/pd would get mine more wired up. If she was really really upset, I would do a quick pu to calm her and then put down. Do you feel like he would sleep better without a swaddle? We didn't swaddle dd as she liked her freedom too much and around 3 months, she started to have better control of her hands. I did and still do have her in a gro bag. When I did shh/pat, you can modify it to what you think suits your baby - for example, some babies don't like the patting, some babies don't like the shushing... I kept mine on her back and patted her thigh and shushed. With all that shh/patting, she eventually found her thumb and learned to self soothe. For naps, I had a pretty strict wind down routine - change nappy/put white noise on and sway to one of the songs on the machine whilst rubbing her back in circular motion, then start patting her bottom and shushing and then in the cot. I would then leave and see what she would do... if she started crying and it was a mantra cry, I would leave her. If she would cry and need me, I would go back and start shh/pat. Some start shh/pat as soon as they place the baby in the cot. I used to give it 20mins of shh/patting (for naps only) and if she wasn't asleep by then, I used to get her out and give her a little more A and as soon as we'd get tired signs, I would try again. If E was due, I would do E and then try again for a nap. If she was getting really upset, I would pick her up, a cuddle or walk around and rub her back and shushhhh and then back in the cot.
It's important to remember that you're still in the early days of sleep training, if he used to be in the swing for all naps and at night and there is expected to be some regression too. Try to stay away from going back old habits (except for that catnap I mentioned before
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) and with time (it took us about 2 weeks) he will learn to self soothe.
Night feeds - yes, if mine had her last feed at 7 and then woke at 11, I would have fed. For me, sleeping through meant anything more than 4hrs and usually babies start to do 4-6hr stretch in the first part of the night and then they wake sometime towards the morning and then go back to sleep for another hour or 2 before they wake for the day.