HardlyW8,
Apparently I was missing your point here, and I'm sorry. I understand now you're flying an award and not a revenue ticket.
TAM is the airline AA uses in South America, for the tag EZE-Brazil. BA also flies this route on some days of the week. So does LanChile, through SCL. Unsure whether you can include BA or LA on this award without it becoming a OW award (thus, guess, requiring a min of 3 OW carriers).
Because you're asking info on awards involving AA miles and another carrier (not AA) I'll leave for the AAdvantge experts to please answer.