I would consider teething if he's showing signs outside of naptime. Meaning, is he chewing alot, does he have reddish cheeks or runny/stinky poos (more so than usual)? These were signs for my dd. Of course teething will disrupt sleep. However, is he perhaps ready to lengthen his A time. Could he have not been ready for his nap? You could try to lengthen say 15 mins and see how he responds to that.
As for feeding to sleep, I suggest you try to work on independent sleep now before it becomes a huge problem later. Rocking my dd was her prop, and I resented it. I don't mean to sound harsh, but being a slave for up to 20 mins to get to sleep was draining on me. Now that she can put herself to sleep, our family is much happier. We can work on this with you if you want to try.
Taking his bottle in "spurts" is actually pretty common. It doesn't have to mess up the routine. Some babies are either to active to sit for that long to be fed, and others need a quick breather before finishing. Think of it more of a thirst quincher while playing. Also, many babies aren't that hungry in the morning even after sleeping all night. My dd eats less in the morning, too. I often worried, but she's perfectly fine. I just reminded myself that I don't particularly like to eat in the morning either (unless coffee counts :wink:).