Welcome to FT

Etihad is not a OneWorld airline. Etihad is an AA partner airline, so if the fare class is eligible you can receive EY miles. Check the fare class carefully on the EY web site.
http://www.aa.com/i18n/AAdvantage/ea...lines/main.jsp

Do you have the QR or EY freq flyer number in the reservation now? You can have a freq flyer number in a reservation and try to change it at check in, but it does not always stick: high risk

Oneworld Ruby is low status and does not entitle you to much
http://www.oneworld.com/ffp/oneworld...82017A2F1B0D6F
Note the " *In accordance with the individual policy of the oneworld member airline operating the flight" foot note

Extra legroom & seat allocation will be as the t&c's of the ticket. As a non AA freq flyer on an AA economy flight keep your expectations very low to nothing. Have you a seat allocation now? If getting EY miles is important I would forget about using your QR status to try for benefits.