AS is not a member of oneworld and does not grant lounge access to oneworld elites. You can receive Alaska Lounge access by purchasing a first class ticket on Alaska Airlines.

You will not receive free bags on an Alaska Airlines operated flight even if codeshared by AA.
See also:
http://www.flyertalk.com/forum/briti...gh-alaska.html
http://www.flyertalk.com/forum/27042667-post599.html
http://www.flyertalk.com/forum/25980302-post544.html