Surely Melbourne will make sure they retain M.Gawn. Also, he is probably a risky player to pay overs on to get him to a new club, given his injury history and only relatively short period of exposed top-level form. It'd be similar to Sydney plucking Mumford, but they were much more well-resourced to handle the fall-out of it going wrong.
Z.Smith would be a good get if he's available as he is talented and a great age for a selection of his type. It might depend on how sure GC are of Nicholls being able to handle the load and some of the other changes for 2016 that we've mentioned (e.g. no sub and the likelihood of GC losing Dixon). Gorringe wanted out from GC last year but they seemingly refused to trade him, from memory, but you'd think it would be harder to keep all three beyond this year. Gorringe might attract some interest again, but I think Smith would be the better of the two - Gorringe might be a cheaper get, though.
I think the likes of Minson, Jamar and possibly even Pyke could find themselves without a team at the end of the year. Jamar is probably finished, but there might be the chance of Minson and Pyke getting a chance elsewhere as mature-aged rookies.