Are you sure you need a macbook air AND an Ipad? if you hve the macbook air, it is super portable and light and you can put it on your lap anywhere for movies and reading. if you also have the SE phone as well, you almost have a mini ipad for when you want to just hold something in your hand to watch a video or read. if you are using the apple ecosystem on your computer like notes, mail, calendar, reminders, icloud they will all sync and work great on the phone. and you will have two devices that are very portable. how will the ipad add to that? it seems redundant to me.
I could see you needing the ipad if your draw a lot or want to take hand written notes for class, or just maybe love the feel of reading or watching a movie while holding the tablet. . in that case, maybe you dont need the mac air. have the ipad as your mobile computer. it does most of what the laptop does, just less efficiently. but maybe even better than a laptop for school because you can draw on docs. instead of a macbook air, you could get an imac or a mac mini for your home base desk (if you have one) because you will probably get better speed, ram and ssd for the same price, which is better for the coding you are doing. in that set up the macbook air is redundant. the only problem i see for you in this setup is if you need to code in class, not sure how good the ipad is for coding.
if you carry the phone with you, not sure you need the watch. i have never seen a reason to have the watch for myself. maybe if you have a health issue and want to monitor some health stats? but my phone is almost always near me, what will the watch really add?
because you are on a budget, basically what I am saying is to think about all the things each device can do, because there is so much overlap, its rare you need all the devices. you can probably solve everything you need to do with laptop + phone or ipad + desktop. no?
