Well, first your logic on 1SE was kinda faulty. I mean you only really gain one FP and killed one in the process. But more importantly, I would never move away from a 6

resource. There are really two main reasons from moving from a SIP position. The first is to improve your capital in some way - more food, more river, better capital position (bureau), bonus to city center (like PH). The second reason is less applicable to you now as it primarily is for the highest levels like Deity where you generally know that city spots will be at a premium - that is, you want to setup subsequent city spots. But moving away from good food is generally a no-no. You did not improve your situation and, if anything, made it worse. 1SE loses a turn and a forest but otherwise gets rid of a bad tile while maintaining the food and adequate cottage locations, while setting up food sharing. Lesser concern is noting the coast can be seen to the east, so your move potentially might cause issues if seafood is present (which it wasn't), but worth consideration.
As Pangaea said, multiple pop citizens reduces happy concerns. But also, it sets up potential better overflow positions, although that is not always a priority very early it can help. I like to whip first settler with as much OF into a new worker. Chops timed can help too. However, it is also about timing. You can whip a 4>2 settler pretty fast - like 1 or 2 turns of production if Imperialistic with Cathy. Or if not IMP, with help from a chop. One pops are not completely out of the question. It all depends on the timing of things and such. You have great food here so can grow really fast, plus with a Mining start you have relative fast access to BW.
While irrigating FPs is not completely out of the question in some situations - lower food. It is a waste of worker turns here. Farming desert takes a lot of turns and just is not necessary here. You should have BW by the time the corns are farmed, so you can start chopping..and TW will arrive not long after to setup road to the new city. Plenty for worker to do.
Granary is not always urgent in the capital especially with such good food, although logic would deem otherwise. It is really about opportunity. If expansive trait you can usually get one really quick from a chop and/or overflow. In this case, you could possible 2pop a granary at some point, which I did in my test. (note: you want the granary to complete on a turn in which the food bar does not go over the halfway point to max food storage) So it is situational. Sometimes I just gradually build the granary putting bits of OF into it until I can complete it at the optimal point. Your first priority though is workers, settlers and spawnbusters.
Should I wait one more turn before whipping or will I lose the opportunity to whip 2 pop?
Good question. Timing for IMP leaders is a little trickier because of the bonus. Much easier to calculate without IMP as one knows that 29H of production (3pop) or 69H of production(2pop) are the clear points for max OF for settlers whips. I'm actually not certain the points for IMP bonus, but usually kinda know if another turn would kill the 2pop. I think generally though that 2 turns is fine enough. You will get 16H of OF but also more because the base production into the settler that turn adds to the overall effect, so there should be a bit more. If you time a chop the following turn you should get a very fast next worker. But also note, that sometimes it is not always about the OF early. I tend to try to maximize it as much as possible, but often the more important thing is getting the next city as fast as possible and moving to the next item.