If you buy an ipad. choose the 32gb one.
Why? because you can store alot of music and photos and movies and apps. the 16gb has only a 13gb usage because of the the ios sofware. also the ipad mini 2 and ipad 4 is similar to each other. Difference only is the screen and the processor.
Camera is the same. I have an ipad 4. Battery lasts long and I love it. drawback, it takes a long time to charge. maybe 6hrs.