code shares
 

if i do a rtw in coach can i ask that the lax hkg be on the aa flight number so that i get aa miles as the cx number would be booked in m earning 0 aa miles?

Of course, but there has to be availability in M (AA may choose to make none available in that fare basis). Codeshares on other Oneworld airlines are allowed, the prohibition is on codeshare flights where the operating carrier is not Oneworld.