I think the people in the house (including the child now) are dead and have nothing to do with the rest of the season. The person who took Clem was obviously the one on the walkie talkie the whole time because of the conversation at the end. It does suck that lee gets bit but i think the final episode will play out like this. You (and whoever you have with you) will spend the rest of the game searching for Clem while having the characters with you dying off one by one in the process. Because let's face it, the characters we choose to live just end up getting killed off anyway cuz its easier for TT (my dearest Carley). Lee will start to feel worse as time goes by but at the end finds Clem but she's in danger and you spend your final moments battling zombies and giving her time to escape. I think it would be cool if Lee turns at the end with a cut scene and you get to play Clem only for a few seconds so you can make her shoot lee in the head.
On my evil Lee im all by myself so it should be interesting to see how that plays out.

Oh and i dont think you'll be able to play as Clem for season 2 because a huge part of the story was how do you survive in this world while protecting this child that needs you and learns from you