Software differences beetween iPad 2, iPad Air and iPad mini (iBooks)

Question

I need to buy an iPad to see how EPUB files are displayed in iBooks app. It is very important to me whether iPad 2, iPad Air and iPad mini (both generations) work exactly the same when it comes to displaying EPUB files in iBooks app.

1. Is there any difference between iOS behaviour on 9,7' iPads an iPad mini? As far as I know, both have iOS 7.0.4 (or can be updated to that version), but it sometimes occur that even with same number version software works differently, so I need to make sure.
2. It looks like newest version of iBooks app is 3.2. Is this version available for both big and small versions of iPads? Is it exactly the same in a way how it renders EPUB files? For example iBooks for Mac is known for working a bit differently than iBooks for iOS hence a question.
3. Is it likely that Apple will support all of those devices the same with future updates of iOS and iBooks app?

Please note that pixel density (i.e. Retina display), speed differences and less processing power are not issue in this question. What matters is rendering of books.

I saw 'Other than size, what's the difference between the iPad Air and the Retina iPad mini?' question, but answers do not provide neccessary details about iBooks specifically.

Answer 1

I don't believe there are any software differences at all between an iPad mini and an iPad 2 or iPad Air. Both iPad minis use the exact same display resolution as their larger counterparts (1024x768 non-retina, 2048x1536 retina), just on a physically smaller screen. The whole purpose of this is to ensure that all existing software works identically on both device sizes.

In fact, I don't think it's even possible for an app to "know" which size device it's running on, since there's no technical way to differentiate them. Apple's own iOS Simulator doesn't even list the iPad mini as a separate device to simulate: the only options are iPad (meaning 1024x768) and iPad Retina (meaning 2048x1536).