Yes, subject to the other oneworld airlines' making award space available to partners.

Note that it is often better to book partner awards with BA Avios rather than IB Avios: BA permits changes/cancellations to partner-award redemptions (for a fee); IB does not.

Once you have an Iberia Plus account and a BAEC account open and funded for at least 90 days, you should be able to transfer Avios freely from one account to the other. Just make sure that your name appears exactly the same on both accounts.

You can also choose to credit flights flown on IB to other oneworld frequent-flyer programs, if and when it is advantageous to do so.