Well, it's hard to make recomendations without more specific reqirements; but I'll give it shot. I'm feeling chatty.
MS Office; of course almost all the major Microsoft Office apps are available on the iPad. As long as you don't need high end features like automatic indexing and pivot tables, they are good. Microsoft does not offer the free version of their apps for any device with more than a 10 inch screen, so you'll have to pay something. I have the Home Single User subscription, which is pretty cheap. I haven't checked recently, but I believe the student account is cheaper with more licenses. Go that way if you can.
The native Photos app is good enough if all you need is basic photo enhancement. I rarely use anthing else, but when I do it's either Snapseed or Enlight. I used to have Adobie Essentials (or whatever it was called) installed, but they keep changing things. At some point it got removed, and I've never had a reason to search for it and re-install (if it still exists). At this point, if I needed a powerful photo/image editor I'd probasbly go with Affinity Photo. It's pricier than most iOS apps, but the feature list and reviews suggest it's more than worth it for those that need the tools.
As far as viewing and organizing photos, the Photo app's iOS system integration make it the easiest to use. Unless there is some feature you can not live without, it's better to learn to work around the few eccentricys of the Photos app than trying to replace it.
Text books is going to depend entirely on your text book source. iBooks,
Amazon, and a few other ebook sources fully support thier textbooks on the iPad (in their own apps). If the textbooks are PDF based, then you have a huge selection of choices. I use Documents by Readdle for most of my PDF reading. If you get their PDF Expert apps as well, Documents will use the more extensive PDF editing tools, but the PDF annotation tools in Documents are enough for most.
Other apps you might look at are Notabilty (good for all kinds of note taking and PDF markup), and Nebo (great handwriting note taker with automatic text conversion). I highly recommend the Apple Pencil for this. Any other stylus is a huge let down after you've used an Apple Pencil. It's not just about drawing, though that's fantastic as well.
Most of the native apps (Notes, Calender, Reminders, etc) are good enough that you don't need to rush finding a replacement. Personal preferences play a big role in these kinds of apps, and there are a lot of really good replacements, so shop around until you find exactly what you want. In the case of Calendars and Reminders, almost all the replacements will use the same account. You don't need to worry about accumulating a lot of data, and haveing to start over.
For myself, I really like the native Notes app. With the new iOS 11 update (I'm on the Public Beta) it's even better. I have not plans on replacing it. I used to use Evernote, but it got to complicated. The've fixed that, but they have also make entry level accounts more limited. The difference is no longer worth the trouble to switch back.
Reminders is basic, but all I need is a basic reminders apps. If I were to upgrade I'd consider either Things or Todoist. I've used both in the past. Things back before iOS, and for a while later. Todoist when I briefly had both Android and iOS devices.
Calenders is ok, but I prefer Fantastical. Calendars 5 by Readdle is a close second for me. Feature wise they are similar. I just like Fantastical's layout a bit better.
Oh, and if you are going to do a lot of typeing you'll want a keyboard. I use Apple's smart keyboard, and it's enough for me. However, If I was going to type for hours a day, I'd probalby get a really good bluetooth keyboard. Not a case style keyboard, or at least not just a case style keyboard. Those are always a compromise. Egonomics are important if you're going to give your fingers a real workout.
Well, that's all I can think of at the moment. Enjoy your new iPad.