It sounds like you are making the right choices for your AOW.
As for EAN/nitrox check with the liveaboard, some and I’m not sure about Blackbeards have you do the book work before the trip and take the test when you arrive onboard so you can use nitrox on the 1st dive. With most liveaboards you are doing 4 or 5 dives a day and if you are not using nitrox you will be running out of bottom time on air tables