St. Louis is going to run with Elliott and Allen as a tandem next season. Allen is their Lehner.
The only pieces that STL could offer to interest me would be Shattenkirk, Oshie or Backes. Just say no to Berglund.
Best fit would be to talk to Chicago with Hjalmarsson as the target. Kane is a UFA after next season and he has been vocal about wanting an actual bonafide center to play with.
St Louis is interested in Spezza, according to a lot of the "talk" these days, and since Ryan Miller isn't going to be signing there they are in need of a goalie. Spezza + Lehner for......well, to be honest, there aren't that many forwards on that team I really want. They work hard, but they aren't prolific scorers and we're going to need scoring if/when Spezza is gone as well as 9MM and Hemsky leaving.
Without anything else near close to NHL ready, I'd say trade deadline. I don't see Andy wanting to stay here afterwards with Lehner being ready in a year or two. Other teams may want him, I'm thinking Calgary if they don't make a move for a starter, plus Burke loves Americans, and Alberta taxes are very low
It is Anderson's job, and Lehner is the back up goalie. Neither of them had a great season last year, but Anderson has proven he's a starting goalie in the NHL while Lehner hasn't but has proven he's got some maturing to do.