I generally don't use Oneworld - but do fly Lan Chile from time to time. I will soon be on a paid J fare in South America. I have no status on any LA carrier. Does a paid J ticket give me lounge access to all OW carriers? I am particularly interested in EZE because I'm arriving on UA and departing on LA and would LOVE to take a shower and assume an OW lounge has one.... Thanks!

Paid J gets any access to any J lounge owned by a Oneworld member, including the Admirals Club. Contract lounges can cause problems. You will get contract lounge access for the J carrier (Lan Chile, in your case), but if you try to get into a contract lounge of another carrier, they may or may not let you in. In any event, the only time I went through EZE, the Lan Chile lounge was a thorough disappointment, basically consisting of a room and a television. The only reason I stayed is because a certain other OW carrier f'd up so badly that I had to go up against LA to get to Santiago and that's where the CSR was. The Admirals Club was closed at the time, but I have been told they have showers, which you will have access to if it's open.

Well the EZE scoop is, LA uses the AA lounge, and there are no showers. There are no "transit" desks for arriving pax (who aren't clearing EZE immigration) - you have to go to the departure gate of your next flight to check in - although the AA lounge arranged for a "precheck-in" by calling LA (confirming passport info, seat, etc).