Which iPad for a confused college student?

I noticed other posts asking WSIB weren't being removed and were actually gaining more traction compared to the usual thread, so I decided to make a post!

TL;DR: W(i)SIB? iPad/iPad air, 11 inch, keyboard + pressure sensitive stylus compatible. USA college student, confused by retailers, student discount and generations.

I had a look through the sub as I am trying to decide on an iPad for college, yet I am only left with more questions! I would love some support in making my final decision.

I am seeking an iPad/iPad air suitable for college, including note-taking and reading books. It is very important to me that I can open and annotate my textbooks (usually they're in PDF format) and take excessive notes! I like the 11 inch model and want a keyboard and pressure sensitive stylus. It is also important to me that I can buy a pastel cover for it (some of the ones I have seen only have dark colors!)

My confusion stems from the following: retailers, generations and tips from peers. I have spoken to numerous classmates about their iPads, and each purchased theirs from a different retailer. Whether it was BestBuy, Amazon or Apple, refurbished or new, they each had their own version! I don't know where I should begin looking. I am on a budget, so refurbished/not directly from Apple is probably better. But I still don't know what to trust.

I also saw plenty of discourse about generations and other specs on this sub, which I had not considered prior. I am not well-versed enough to determine how generations impact my needs. Would someone be able to help me in this department?

Moreover, I had classmates tell me that with a student discount you can get a magic pen/airpods for free. I didn't see this on the Apple website, however, so it only confused me more. 

Finally, I would like a folio cover that has a magic keyboard built in. Is this an option, or did I hallucinate it? 

I did go to the Apple store, but unfortunately I seemed to know certain things better than they did about what they iPad could do..! So I could really use the help of some of you guys.

Thank you in advance for your help!