Screen Rant has a very nice article regarding the possibilities of Bane in TDKR. Since this is going to be a "new interpretation" of the Bane character, we might probably end up seeing an amalgamation of characters in Bain. We must keep in mind that one of Bane's main characteristics (from the comics) is that he is pretty much a genius, a person who grew up in a very, very violent environment who demonstrated early in his childhood and development a high capacity for learning; in the comics he developed a master plan to weaken Batman and solely by observation deduced Batman's true identity. Therefore, we might see in Nolan's Bane some characteristics shared by other Batman foes, say like: Dr. Hugo Strange. Dr. Strange was obsessed with Batman and also figured out his identity, and was also a genius; so, who's to say that we my see a Bane/Strage amalgamation in Nolan's Bane character? Who knows, but for me, that'll be something interesting.
Also, on Selina Kyle, she could be a high-end, socialite prostitute/call girl who moonlights as a thief by knight, who somewhat gests involved with Bruce Wayne; although the possibility of Wayne getting involved with a call girl is kind of far fetched, she could share some of the same high-end social events, as an escort for some big-money fat cats, the kinds of friends someone like Wayne may have ("a fundraiser with my pals, you'll never need another cent..."), a kind of character that could also be fascinated with Batman and tries to find his identity.
The possibilites are endless, but we have to trust that Jonah and Chris Nolan have come up with a intelligent and cohesive story and script that will give us one great epic final Batman movie.