There are only certain games that will allow you to log in to a second account to play split screen such as Sacred 2 and Borderlands, but Resident Evil 6 is not one of them. However you can play split screen in Resident Evil 6.
If you are having trouble creating another account on your PS3, just go all the way to the left on the XMB(main screen) and select Add new profile. Follow the on screen directions and you can make as many accounts as you want and not worry about having to pay for Xbox Live.
Only the very first models have backwards compatibility with PS2. If you have any other model besides the original release versions of the PS3, it will only be able to play PS3 and PS1 games. If you bought an older model PS3, you can check on the playstation website if it is a backwards compatible model. If it is, you have to download the PS2 software from the Playstation store in order to play it.
Are you asking if we are going to rent it or are you asking if gamefly is going to get it? Gamefly gets all disc based games, if that is what you are asking. I do not believe that game is a disc based game, so I don't think they will be getting it.