This seems like an issue where the entitlement hasn't been applied correctly, double check that you are signed into the EA account that you applied your Celebration Edition to, if you are and are still not seeing all your unlocks in your Collections you will need to contact EA Help with proof of purchase (email receipt, order number etc)) of the edition so that they can apply it to your account manually.

You can begin that process via the following link; https://help.ea.com/en/contact-us/?product=star-wars-battlefront-ii&platform=pc&category=missing-content&issue=never-received-content

Sorry to see that you're experiencing problems, hopefully the team can get you up and running on the battlefront!